Now this is exciting. Animar is an powerful threat that dodges a large amount of removal in the format (only really dying to bolt). This is one of the cards that might enable a new archetype.
Now we have something interesting. This would likely play a similar role to cards like Maelstrom Pulse giving red decks (Skred i'm looking at you.) some catch all answers. The downside is pretty minimal, although it isn't something to be ignored either.
Now this is a card that might bring new life to a old archetype. This is perfect for Scapeshift, Voyage already sees some legacy play in ramp decks because of the lack of basics, and modern is the same.
Finally, now this is a good one. Edric is a powerful card advantage engine that slots into bant spirits, could see play in elves, and may even breathe new life into a temur midrange deck. Edric is a prime contender for one of the better cards in the set for modern.
The elephant in the room, and a card that presents one of the biggest arguments against this hypothetical change. Flusterstorm is a powerful counterspell that is INCREDIBLY expensive for what it does. With the lack of any real reprint and the tiny supply, if this card saw any resemblance of play (which it would) It would go up even higher. Granted this card is replaceable, (and would probably be the end of storm for good) so maybe this is not as much of a issue as I think it will be.
I think Karador has a slightly higher chance than Kaalia, but will need a dedicated deck for it, like a more graveyard centric abzan. More than likely it's probably better to just play dredge.
This card gets my brewing gears turning. If there is a combination of cards in modern that make this card an instant win (say Akroma and deaths shadow) I could see a new deck being created.
While it won't replace Path to Exile In decks like enchantress and maybe jeskai nahiri it might have a shot.
Well that's all for part 1. Part 2 will come out when I feel like it. In the future I will probably just talk about cards that are worth mentioning, so I don't have to keep saying "Well its a 6+ drop that doesn't do anything..."
Since this has been out of print for 5 years, everything that hasn't had a reprint is slowly creeping up in price. If these were introduced into modern, they would need reprints to keep prices from being bonkers.
Also, I agree with most of your assessments especially collective voyage. However, chaos Warp is actually a bonkers powerful card. 3 mana instant speed answer to anything. The drawback isn't negligible, but generally it won't be anywhere near as important as what you got rid of given that between lands and non permanents, most of the time you are giving little if any value.
Edit: I could see Mimeoplasm being a cross between Dredge and Grishoalbrand
Link to descusions on this topic:
A Modern Proposal
What if commander / conspiracy / planechase exclusive cards were in modern
Ok lets start with the original commander set.
Acorn Catapult
This card is pretty bad, and likely won't see any play.
Alliance of Arms
With the existence of Secure the Wastes I doubt this would see any play, unless there is a deck that really wants to give your opponents creatures.
Animar, Soul of Elements
Now this is exciting. Animar is an powerful threat that dodges a large amount of removal in the format (only really dying to bolt). This is one of the cards that might enable a new archetype.
Archangel of Strife
Avatar of Slaughter
Same deal with Archangel, this is a purely commander card. Modern doesn't have any need for 8 drops that don't win the game on the spot.
Basandra, Battle Seraph
Very unexciting, if modern wanted a 5 drop angel they have Avacyn and Baneslayer.
Celestial Force
Continuing on the big dumb creature train, we have this lovely do nothing. A 7/7 that gains some life for 8 mana isn't going to do anything in modern.
Champion's Helm
This card was made specifically for EDH. The swords don't even see much play in modern, so there is little hope for the helmet that could.
Chaos Warp
Now we have something interesting. This would likely play a similar role to cards like Maelstrom Pulse giving red decks (Skred i'm looking at you.) some catch all answers. The downside is pretty minimal, although it isn't something to be ignored either.
Collective Voyage
Now this is a card that might bring new life to a old archetype. This is perfect for Scapeshift, Voyage already sees some legacy play in ramp decks because of the lack of basics, and modern is the same.
Command Tower
Crescendo of War
The only chance of this seeing any play is in something like B/W tokens, but at 4 mana I highly doubt it has much chance.
Damia, Sage of Stone
Damia is cool, but that's about it. it's possible to be a prime reanimation target, but there are much better options out there.
Death by Dragons
Dread Cacodemon
Meh... If this could be reanimated and still get the trigger I could see it being a player in esper rights decks, but as is...
Edric, Spymaster of Trest
Finally, now this is a good one. Edric is a powerful card advantage engine that slots into bant spirits, could see play in elves, and may even breathe new life into a temur midrange deck. Edric is a prime contender for one of the better cards in the set for modern.
Flusterstorm
The elephant in the room, and a card that presents one of the biggest arguments against this hypothetical change. Flusterstorm is a powerful counterspell that is INCREDIBLY expensive for what it does. With the lack of any real reprint and the tiny supply, if this card saw any resemblance of play (which it would) It would go up even higher. Granted this card is replaceable, (and would probably be the end of storm for good) so maybe this is not as much of a issue as I think it will be.
Ghave, Guru of Spores
Nothing much to talk about, there are better 5 drops in modern.
Homeward path
Get out your tinfoil hats, because I have a challenge for you. And it is quite dubious....
Hydra Omnivore
Meh..... same reason as all the other big fatties.
Kaalia of the Vast
I like kaalia, and it might be good enough. Cheeting in a avacyn or Grislebrand seems like a lot of fun.
Karador, Ghost Chieftain
I think Karador has a slightly higher chance than Kaalia, but will need a dedicated deck for it, like a more graveyard centric abzan. More than likely it's probably better to just play dredge.
Magmatic Force
Maybe reanimation target..... eh...
Mana-Charged Dragon
Its a shivan dragon.
Martyr's Bond
This effect is probobly a bit too much mana for modern, although I could see it in the Enduring Ideal decks as a 1 of.
Minds Aglow
Great in EDH, not really anywhere else.
Nin, the Pain Artist
Nin might be cool for standard, but modern... not so much.
Riddlekeeper
It's greatest riddle is why you should play it in constructed. The answer: you should not.
Riku of Two Reflections
It't too expensive for modern.
Ruhan of the Fomori
A 4 mana 7/7 is pretty strong, but being 3 colors really hurts it's chances.
Sewer Nemesis
I'm sure there's some joke about this card being garbage...
Shared Trauma
There are much better mill spells in modern.
Skullbriar, the Walking Grave
Skullbriar is cool, but with ought a way to easily reanimate it I doubt is is strong enough.
Stranglehold
This is not blood moon.
Syphon Flesh
Paying 5 mana for an edict and a 2/2 is very underwhelming.
Tariel, Reckoner of Souls
Another card on the big dumb creature list.
The Mimeoplasm
This card gets my brewing gears turning. If there is a combination of cards in modern that make this card an instant win (say Akroma and deaths shadow) I could see a new deck being created.
Trench Gorger
The only appeal of this card is a way to get all the lands out of your deck. But for 8 mana there are better things to do.
Tribute to the Wild
Disenchant is better.
Vish Kal, Blood Arbiter
Yay.... more do nothing 7 drops.
The Vow cycle.
Zedruu the Greathearted
As much fun as Zedruu is, This lovable Minotaur (that looks nothing like a Minotaur) won't be having fun in modern.
Soul Snare
While it won't replace Path to Exile In decks like enchantress and maybe jeskai nahiri it might have a shot.
Well that's all for part 1. Part 2 will come out when I feel like it. In the future I will probably just talk about cards that are worth mentioning, so I don't have to keep saying "Well its a 6+ drop that doesn't do anything..."
Also, I agree with most of your assessments especially collective voyage. However, chaos Warp is actually a bonkers powerful card. 3 mana instant speed answer to anything. The drawback isn't negligible, but generally it won't be anywhere near as important as what you got rid of given that between lands and non permanents, most of the time you are giving little if any value.
Edit: I could see Mimeoplasm being a cross between Dredge and Grishoalbrand
Marath, Will of the Wild Tokens!! / Karrthus, Tyrant of Jund Dragons! / Muzzio, Visionary Architect / Brago, King Eternal / Daretti, Scrap Savant / Narset, Enlightened Master / Alesha, Who Smiles at Death / Bruna, Light of Alabaster / Marchesa, the Black Rose / Iroas, God of Victory / Freyalise, Llanowar's Fury / Omnath, Locus of rage / Titania, Protector of Argoth / Kozilek, the Great Distortion
Modern
Elves / Titanshift / Merfolk