If you don't want to do 25man Ulduar, then just don't do 25man Ulduar. If you're not in there, you don't need the next tier of loot, so you don't get it.

Not having the new uber gear doesn't stop you from playing and doesn't interfere with a "casual" playstyle. In fact many, many WoW players are never on the cutting edge - never on the final raids for endgame. They're always a tier or two behind on the raiding scheme (myself included). There's nothing wrong with that.

No one is saying, "You must do 25 man Ulduar and you must have the new badges to keep playing."