Just letting you know the old rita is exactly the same, she just accidentally had the text of the new rita put on her, she still heals fine.
The old Aberion is fine, just works with a more late game version of Flame Dawn, especially if splashed with 1 genesis, I've had a 72/72 unstoppable aberion before.
Demon of Fear and Karani were done to put the factions a bit more where they should be before gold launch and is an exception more than a rule.
as to the warped swarmer, it might have been a too big a change, but it either needed a rework or to have it's cost much higher (like 4-5 maybe) as it was too good for a 2 cost, and that shows as it was being run by non-swarmer decks.
These are of course just my opinions, and it must be said that I also play with some wonky fun decks (like Ultra unit for example)