Fox's Up-tilt is much better than Ryu's. Ryu's despite having a large hitbox, it is only good for True Shoryuken confirms while Fox's Up-tilt is massively disjointed to the point it hits in front of him, frametraps by literally hitting the opponent, catches ledge getups, combos into everybody's favorite 16% Up-Air strings, vortexes, combos into itself, kills at higher percents and much more. I'd go so far as to say that Fox wouldn't be top tier without that move, as its his best grounded move. Without Up-tilt, Fox can't do half the things he can do in neutral or advantage. Most of his good combos would be gone as well.
Toon link still has a top 5 Up-tilt though...
Edit: Bayonetta's Up-tilt is a slightly better version of Mario's, but nowhere near as good as Fox, Kirby, Ryu, or Toon Link's.