Everything that changed for the worse from the beta period.
Gameplay
No more grounded neutral air.
The camera zooms in far too often.
No leaderboards.
No after-battle report aka "damage done" "ringouts"
You can't see who accepted/declined a rematch.
Modes
No more Co-op VS AI
No offline play
No FFA mode with items
Training
You can no longer play as characters you don't own in local play and training
You can't change your controller settings in the training room anymore
More full loading screens when changing settings / start positions
No advanced tutorial mode
Economy / Progression
No more cheaper characters (e.g. Garnet, Taz) for 1500 - every character is 3-6k
No non-Gleamium skins
No more battle pass xp after every match. We can only level up the battle pass from challenges now.
No "toast back" if someone toasts you after you've left the post-match screen.
You HAVE to use your character tickets if you got them (presumably also battle pass tickets), you can't choose to pay character currency or gleamium.
Settings
No option to remove team colors in battle
No ability to swap neutral and side attacks
Can't remove or lower buffering of inputs
Can't change the game's language in the settings
Add your suggestions and I'll update the list. Going to stay away from balance changes since those would be their own post by themselves.