At least, Unstable Evolution will live on in some fashion after rotation. I highly doubt this spell will be used much but I am happy to see that Evolve continues to be part of Shaman. *votes as playable*
if i'm dead honest here evolve shamman can end up being a wild archetype with enough cards in the pool, so far it doesn't work because there aren't enough evo support cards but this might push it, i mean Resurrect shamman was a t1 deck in wild at some point
Big priest was never a problem until Lesser Diamond Spellstonegot printed, and this spellstone breaks way too many decks asides from big priest, basically compare it to gallery and you can see that spellstone should cost more than gallery, barnes isn't a problem in any other deck, spellstone tho, spellstone is a problem in many different priest decks both in standard and wild.
Not great given the current standard pool, but I think it's getting more hate than it warrants. Evolve effects have been powerful in the past, and deathrattle (re)summons add resiliency to aggro and midrange decks when trying to navigate the glut of removal that control decks have these days.
Turns out this card is a much slower, uncontrollable iteration of Unstable Evolution (which doesn't see play outside of meme decks, see Kiblers EvolveFrog) and barely playable as long as there are minions such as Corridor Creeper or Giggling Inventor (too slow since the nerf, see Token Shaman).
Crusher Shaman was a thing like 3-4 yrs ago, nowadays it's just outdated with all the efficient removal. And this type of deck will be no different.