Make all Limit breaks usable.

I think once you reach the threshold, you should unlock the Limit for that level and keep all the lower level limits. Maybe we can somehow make the weaker limits scale up with level as well. Limiting your character to a single limit kind of makes all the prior ones useless.

That's one of the Ultimate perks. If you are set to Break 4 you can still use Break 1 2 and 3 but if you change to Break 3 you can only use 1 2 and 3 but will have faster limit charge.