The main reason it needs to be "encoded" and not "imprint" is likely to avoid uncomfortable interactions with previous imprint cards. Say you imprint it on a Duplicant....
Flavorwise, I always believed that Golgari zombies were not so much a magically reanimated corpse, but rather a regular old corpse granted a semblance of life by symbiotic plantlife- You have your motile, belligerent plant that essentially uses the corpse as a puppet to move about. Scavenge here makes this theory even more flavorful, as the animating plant just hitches a ride on whatever else happens to wander by.
This also helps explain the haste. Sure, modern zombies tend to be a bit speedier than their classic counterparts, but animated plantlife tends towards either the completely immobile or the frighteningly quick (sometimes both, with an immobile tree or stalk base with lightning fast branches/creepers). I hope there's a high power defender with scavenge to represent the other end of that spectrum.
It seems they would be much more likely to just bump the "problem" cards up to rare. Even then, a lot of these cards are only really good in limited to begin with and may never make the leap to constructed. Minimizing the chance that they show up in the only format they make an impact in seems a bad idea.
Deadeye Navigator and any decent ETB creature. If you untap, this is very difficult to disrupt as the Navigator can always flicker itself to dodge removal.
When Ravnica was first released, I was really expecting either the Izzet or Simic to be enchantment-themed (primarily due to Drake Familiar, Bramble Elemental and the Galvanic Arc cycle of Auras). Guildpact cut the Izzet out of the running, and I was absolutely positive Simic would be all about the auras- I mean really, a guild devoted to honing and improving lifeforms to perfection, how could it NOT be? Evidently, Graft and sadface.
So the seeds are certainly there already for an enchantment theme, and at the very least we'll hopefully get a Simic mechanic that doesn't blow. Hell, even if it's just "Simic (This creature has hexproof as long as it has an Aura attached to it.)" I'd be happy.
Story-wise, I expect to see Jace (and whatever other planeswalkers are relevant to the story) convincing Niv that whatever nefarious designs Bolas has for Ravnica need to be stopped, probably by appealing to his self-interest or even ego. It's also not hard to imagine Niv wanting to match wits with Bolas just for the intellectual challenge/bragging rights of it. [EDIT: Also, it's Holmes vs. Moriarty, only with FREAKIN' DRAGONS!]
I really hope Niv doesn't show up as a planeswalker himself. Yes, Bolas is the only dragon planeswalker, but that (like Niv's NOT being one) is part of what makes him so kick-ass. Niv as a planeswalker therefore lessens the awesomeness-impact of TWO flagship dragons.
In the worst-case scenario, all of the flicker effects let your soulbound creatures dodge removal, then flicker back in to keep the soulbound going and keeping your opponent from completely wrecking you during combat. I expect that to be HIGHLY relevant in limited, possibly more so in constructed if soulbound makes an impact (which seems likely).
If we get even a couple of good ETB creatures, this theme will likely form a new archetype, limited or otherwise.
If they add multicolor to the core set, I'd expect between 10-15 cards (not including mythics). Keeping them out of common would certainly add more to the "wow" factor for new players, but it would make sense to at least include them at uncommon so that they can still matter in limited. With so few, it also wouldn't be necessary to include too much mana fixing- most limited decks will be two colors already, obviously, so slipping them in isn't an really an issue unless you're splashing an off-color one, not really any different from any other off-color card you'd splash, trading power for consistency.
Delve is probably a little too "graveyard matters" for a set that's not graveyard based. It could still show up- Future Sight wasn't technically a GY set after all- but I wouldn't expect to see it in large numbers.
I don't think Avacyn herself points to exile. There's plenty of existing answers to her spread across enough colors already. Worst case, you can always stick her in a Helvault- how thematic! Having a set based on cards that wreck your poster-girl seems a poor marketing choice.
This still leaves the possibility that the theme will be "exile your own stuff". Creatures that can be played from exile are perfectly reasonable if they don't have a built in way to exile themselves- again, stick 'em in the Helvault- even more thematic! The Helvault has been broken so it is no longer capable of holding things for long.
ETB and leaves play effects seem a little too... generic to be a theme. That, and Saving Grasp would then be a better teaser. ETB shows up everywhere, and leaves play splits hairs with dieing.
That being said, I have been enjoying Undying Eviling my Solemn Simulacrums in casual, and I'd love to have more creatures that grant that kind of value.
MaRo's article states that Helvault is a mechanical teaser for Avacyn Restored. To be truly useful in that context, it seems likely that you'll want to be exiling your own creatures. I'd expect either "when exiled" triggers or abilities that can only be played from the exiled zone.
This shouldn't really be much of a surprise. Changing "remove from the game" to "exile" greatly streamlines the ability to create these sorts of cards.
Particularly of note when you compare the art to the rest of his gallery- which includes every other guild charm.
Either a)the site used placeholder art for lack of available real art, b)Boros phoned in this (and only this) charm, or c)fake card is fake.
This also helps explain the haste. Sure, modern zombies tend to be a bit speedier than their classic counterparts, but animated plantlife tends towards either the completely immobile or the frighteningly quick (sometimes both, with an immobile tree or stalk base with lightning fast branches/creepers). I hope there's a high power defender with scavenge to represent the other end of that spectrum.
So the seeds are certainly there already for an enchantment theme, and at the very least we'll hopefully get a Simic mechanic that doesn't blow. Hell, even if it's just "Simic (This creature has hexproof as long as it has an Aura attached to it.)" I'd be happy.
Feel free.
Technically even a Shivan Dragon can fend off Nicol Bolas, Planeswalker if you get the drop on him and feed it enough R.
Story-wise, I expect to see Jace (and whatever other planeswalkers are relevant to the story) convincing Niv that whatever nefarious designs Bolas has for Ravnica need to be stopped, probably by appealing to his self-interest or even ego. It's also not hard to imagine Niv wanting to match wits with Bolas just for the intellectual challenge/bragging rights of it. [EDIT: Also, it's Holmes vs. Moriarty, only with FREAKIN' DRAGONS!]
I really hope Niv doesn't show up as a planeswalker himself. Yes, Bolas is the only dragon planeswalker, but that (like Niv's NOT being one) is part of what makes him so kick-ass. Niv as a planeswalker therefore lessens the awesomeness-impact of TWO flagship dragons.
Exactly. This card exists because it's a cute mirror of Zombie Apocalypse and shows how the humans are pushing back the forces of darkness.
If we get even a couple of good ETB creatures, this theme will likely form a new archetype, limited or otherwise.
I don't think Avacyn herself points to exile. There's plenty of existing answers to her spread across enough colors already. Worst case, you can always stick her in a Helvault- how thematic! Having a set based on cards that wreck your poster-girl seems a poor marketing choice.
This still leaves the possibility that the theme will be "exile your own stuff". Creatures that can be played from exile are perfectly reasonable if they don't have a built in way to exile themselves- again, stick 'em in the Helvault- even more thematic! The Helvault has been broken so it is no longer capable of holding things for long.
That being said, I have been enjoying Undying Eviling my Solemn Simulacrums in casual, and I'd love to have more creatures that grant that kind of value.
This shouldn't really be much of a surprise. Changing "remove from the game" to "exile" greatly streamlines the ability to create these sorts of cards.
Leaving mana up for Mana Leak is also a decent way to flip Villager without "skipping" a turn. Or any instant, for that matter.