What the deck is missing is some form of card draw imho or ways to find your key pieces to leverage the mana and not "brick out".
I wonder if Board the Weatherlight can fill this role backed up by Thalia's Lancers.
Gideon Blackblade might not be amazing in the deck but it isn't easy to remove and can protect some key creatures or gain life by giving them lifelink. Gideon of the Trials on the other hand is a good defensive card as well which helps prolong the game until we can hit our mana and I think it should be included in any version of the deck.
History of Benalia is just a good value card that can someties win games by itself or just really tax opposing resources by making them spend removal on it and/or the tokens.
Sure it only adds devotion for a limited time but the floor of it is better than most 3-mana creatures.
My main concern with this deck is the high mana curve but I'm not sure what to do about it as there aren't any real good options in the 1-2 mana slots (besides those that are already included).
Another card worth considering is History of Benalia which can provide devotion for a couple of turns as well as blockers.
It can work offensively as well, especially with Knights as the 2-drops of choice.
Past devotion decks also used to run Mastery of the Unseen which I found a bit weak but it may be good enough in this format.
I actually quite like Knight of the White Orchid as a 2-drop option as even if it doesn't ramp its floor as a 2/2 first-striker with 2-devotion isn't too bad and multiples block really well together. Brimaz, King of Oreskos is one of the better 3-drops in White and I'd want it here.
Why don't you have Dovin's Veto in the SB ?
It is the best counterspell in the format and comes in really handy ramp/combo decks (and also Control if it shows up).
I generally prefer it to the Needle (Spyglass/Revoker) cards.
I haven't considered Sky Tether but it doesn't seem half-bad to be honest, almost a 1-mana Pacifism for this deck.
Another potentially playable 1-mana removal card can be Searing Light to deal with smaller creatures from aggro decks.
Azorius Charm always seemed like an interesting option as besides the tuck attackers option it can just help race even better with the lifelink mode.
I wonder if it can be better in the Blessed Alliance slot as I don't see too much indestructible/hexproof creatures anyway and racing them would work just as well most of the time.
I wonder if Unsubstantiate can work in this deck as a bad Remand of sorts for tempo purposes.
I'm not high on Hanged Executioner as it seems too low impact and the removal mode comes too late.
What's your take on Bygone Bishop as a way to grind out some card advantage post-board ?
You should give Rally of Wings a try as it is really good in the deck.
I'm not sure about those PW's:
# Ashiok, Dream Render - doesn't work with Drown in the Loch and is more of a SB card imho.
# Ashiok, Nightmare Weaver is interesting though not sure if it really excels at anything.
# Narset, Parter of Veils - the deck has too many lands + creatures for the minus ability to be really good so it seems more like a SB card against control to me.
No, Iconic Masters isn't a Modern-centric reprint set (like Modern Masters) so all the reprints there stay legal according to their original printings only.
So Thran Dynamo remains a Legacy/Vintage-legal card.
I'm probably going to to concede that Scorn isn't ideal in this deck but after playing with it some more I rather like the rest of the deck so far (not sure about the SB though).
I'm probably going to replace Scorn with either 4x more removal/burn spells or 2x of them and max out on Scavenging Ooze which has been performing very well so far and might be worth the full playset in the maindeck.
I haven't tested Stubborn Denial in tbe deck as it didn't seem to have enough support but maybe I haven't assessed it correctly and it could actually be pretty good.
I like the flexibility that Knuckleblade brings and it can defend pretty well unlike Borrower. Bonecrusher doesn't seem bad and is much easier to cast but is more of a narrow focused aggro card imho (though it is surely playable in a midrange deck as well).
I wonder if Board the Weatherlight can fill this role backed up by Thalia's Lancers.
Gideon Blackblade might not be amazing in the deck but it isn't easy to remove and can protect some key creatures or gain life by giving them lifelink.
Gideon of the Trials on the other hand is a good defensive card as well which helps prolong the game until we can hit our mana and I think it should be included in any version of the deck.
History of Benalia is just a good value card that can someties win games by itself or just really tax opposing resources by making them spend removal on it and/or the tokens.
Sure it only adds devotion for a limited time but the floor of it is better than most 3-mana creatures.
Here is my initial take on the deck:
4x Thraben Inspector
4x Knight of the White Orchid
3x Banisher Priest
3x Boros Reckoner
1x Brimaz, King of Oreskos
1x Thalia, Heretic Cathar
1x Heliod, God of the Sun
3x Archangel of Tithes
1x Gisela, the Broken Blade
4x Thalia's Lancers
1x Archangel Avacyn
1x Lyra Dawnbringer
1x Gideon of the Trials
1x Gideon, Ally of Zendikar
1x Elspeth, Sun's Champion
Enchantment (7)
1x Legion's Landing
4x History of Benalia
2x Banishing Light
Land (23)
4x Nykthos, Shrine to Nyx
2x Castle Ardenvale
17x Plains
3x Rest in Peace
2x Declaration in Stone
2x Brave the Elements
2x Gideon's Intervention
2x Banishing Light
2x Sorcerous Spyglass
1x Disenchant
1x Shalai, Voice of Plenty
I'm not sure if Banisher Priest is good enough here so maybe Stasis Snare is the better removal option.
Board the Weatherlight would have 18x hits (6x Creatures, 3x PW's, 5x Enchantments and 4x Nykthos)
in this deck so I wonder if it can be good enough.
and you can even add The Gitrog Monster to the deck.
It'd work well to get more triggers out of Tracker.
I was surprised not to see more PW's in this deck besides the flip Nissa.
It can work offensively as well, especially with Knights as the 2-drops of choice.
It seems better than Expedite.
Secure the Wastes and Finale of Glory though not working with Always Watching is a downside for the go-wide plan (Spear of Heliod can be an alternative).
Benalish Marshal can also be good for the tokens plan.
Elspeth, Sun's Champion is a rather obvious payoff for the deck.
Past devotion decks also used to run Mastery of the Unseen which I found a bit weak but it may be good enough in this format.
I actually quite like Knight of the White Orchid as a 2-drop option as even if it doesn't ramp its floor as a 2/2 first-striker with 2-devotion isn't too bad and multiples block really well together.
Brimaz, King of Oreskos is one of the better 3-drops in White and I'd want it here.
The 3-mana Gideons seem like a solid inclusion as does Gideon, Ally of Zendikar.
A rather clunky but potentially devastating removal option can be Quarantine Field (as mass-Banishing Light).
I don't know how necessary it is but Thalia's Lancers can be useful to tutor for either: Nykthos, any PW or some other legends.
It is the best counterspell in the format and comes in really handy ramp/combo decks (and also Control if it shows up).
I generally prefer it to the Needle (Spyglass/Revoker) cards.
I haven't considered Sky Tether but it doesn't seem half-bad to be honest, almost a 1-mana Pacifism for this deck.
Another potentially playable 1-mana removal card can be Searing Light to deal with smaller creatures from aggro decks.
Azorius Charm always seemed like an interesting option as besides the tuck attackers option it can just help race even better with the lifelink mode.
I wonder if it can be better in the Blessed Alliance slot as I don't see too much indestructible/hexproof creatures anyway and racing them would work just as well most of the time.
I wonder if Unsubstantiate can work in this deck as a bad Remand of sorts for tempo purposes.
I'm not high on Hanged Executioner as it seems too low impact and the removal mode comes too late.
What's your take on Bygone Bishop as a way to grind out some card advantage post-board ?
You should give Rally of Wings a try as it is really good in the deck.
# Ashiok, Dream Render - doesn't work with Drown in the Loch and is more of a SB card imho.
# Ashiok, Nightmare Weaver is interesting though not sure if it really excels at anything.
# Narset, Parter of Veils - the deck has too many lands + creatures for the minus ability to be really good so it seems more like a SB card against control to me.
Nightveil Specter doesn't seem great to me and its ability is far worse than Thief of Sanity.
I'd consider replacing it with Brazen Borrower (or Nimble Obstructionist) as a flying threat.
Curator of Mysteries might also be an option as either a threat later in the game or a cycler earlier which can be reanimated with The Scarab God.
Sphinx of Foresight isn't a bad flier either with a useful scry ability.
The deck otherwise has some decent threats and interaction so I'd probably look to add some more card draw or card filtering.
Shimmer of Possibility, Discovery // Dispersal, Strategic Planning and Notion Rain (a better Read the Bones).
The deck could probably support a couple copies of Dig Through Time (or at worst Drawn from Dreams).
The PW's I'd prioritize are:
Jace, Vryn's Prodigy, Liliana, the Last Hope and a 5-mana option between Liliana/Ob Nixilis/Jace.
Jace, Architect of Thought isn't too bad either but seems weaker than the other 2x Jaces.
The deck should be much better without Veil of Summer in the format.
Jace, Vryn's Prodigy, The Scarab God and Murderous Rider/Brazen Borrower.
Some good PW's can be: Liliana, the Last Hope, Liliana, Death's Majesty and Ob Nixilis Reignited.
Some decent interaction in the colors besides the spells already mentioned can be:
Tyrant's Scorn, Cast Down/Murderous Cut/Hero's Downfall and Disallow.
Notion Rain is not bad as a card draw spell and Discovery // Dispersal is decent as well for card selection and GY filling.
So Thran Dynamo remains a Legacy/Vintage-legal card.
Burglar Rat (or Mardu Skullhunter), Yarok's Fenlurker and Brain Maggot/Kitesail Freebooter.
Also 1-mana discard is important even situational like a split of Duress with Despise/Divest.
I'm probably going to replace Scorn with either 4x more removal/burn spells or 2x of them and max out on Scavenging Ooze which has been performing very well so far and might be worth the full playset in the maindeck.
I haven't tested Stubborn Denial in tbe deck as it didn't seem to have enough support but maybe I haven't assessed it correctly and it could actually be pretty good.
I like the flexibility that Knuckleblade brings and it can defend pretty well unlike Borrower.
Bonecrusher doesn't seem bad and is much easier to cast but is more of a narrow focused aggro card imho (though it is surely playable in a midrange deck as well).