Other than like... Mr. Smite, and Celestial Alignment (with Lady Anacondra), I don't actually think Year of the Griffin was too bad for "power creep".
Even those aren't really examples of power creep.
The main thing I think I'll take away from Griffin is that they just did not care that much if a card combo was really over tuned, printing a cavalcade of cards that were high impact from hand. And too many inevitable combo decks.
Also giving lots of efficient value cards to tempo and aggro decks. Which... just kind throws the whole game off. Which is maybe a good thing, but I don't like it.