I can't think of a single indirect nerf.
Grabs were nerfed across the board, which is a benefit for a character with trash throw game and historically has had trouble beating shield.
He had one of the highest air speed buffs in the game.
His dash speed was increased
He benefits tremendously from mobility options as the "mobility" character
Some big direct buffs:
- Shine is much better, coming out faster, with intangibility, and can shine spike once again
- Firefox is harder to edgeguard, with a much larger hitbox and significantly higher knockback (stagespikes very easily)
- Usmash is insanely good - now with a giant hitbox, sourspot behind him returns (entirely absent in Sm4sh), and it now sweetspots on BF platforms
- Dtilt is pretty crazy now - disjoint that combos into everything
- Nair was buffed again and it's probably competing with one of the best aerials in the game
Kill options weren't nerfed so I'm not sure what you're talking about. His Fsmash is a ton stronger, Usmash is way better, Dsmash is more or less unchanged, Uair still handily kills. He actually has an easier time killing now as shield is generally weaker which was Fox's principle issue before and with the air dodge changes he also is even better at vortexing opponents.
But yeah his illusion sucks now.