Just looking through Shim’Zar cards I learnt:
Lyonar has 3 playable cards there: Lucent Beam, Afterblaze and Sun Wisp. Npthing really critical.
Hai will lose Katara, Battle Panndo, Ki Beholder, Onyx Jag and Crescent Spear. Katara is critical, Crescent Spear is a main card for Arti and Burn - so that’s sad. Others are decent, but not critical.
Vets will be hit really hard: Falcius, Whisper, Pax are very necessary, especially the first one. Additionally I will miss Spinecleaver.
Abyssians’ losses are kinda strange: Ooz, Azalea, Klaxon and Obliterate removal will make Creep archetype obsolete without heavy additions. Really, I think Obliterate should be added to core, Cass Variax is too damn slow. Lurking Fear is another lone archetype enabler that will be lost forever. Sphere of Darkness and Gor are also very useful, I’ll miss them.
Magmar has nothing really important for the most popular archetypes there. However, Moloki is the lone Grow Archetype enabler, and also there’s lots of egg support there, strange to see it all rotated away with the new general added.
Vanar has Aspect of Shim’Zar, which will fortunately be removed. Some weak Vespyr support rotation won’t change much, but winter’s wake will certainly be missed.
Neutrals are mostly crap however, nothing to see here.
As a result I must say that we don’t lose much critical stuff with Shim’Zar rotating out, TBH. Most concerns are Abyssian, Abyssian (not a typo) and Vet, but I believe CPG understands all the issues here better than me.
So, I’ll certainly be playing until they remove all those sweet arcanysts from AB. Then I’ll be really upset.