IMO.

The ailerons on most trainers are undersized to do any rolls. I know mine won't. If high rates and adjustment on the control horn won't do it..... A guy at my field has a trainer that he glued 8" of 1-1/2" x 1/8" balsa sheet to his ailerons. While it's not pretty, I assure you, it'll roll now! I was suprised how agile his trainer is, wheras mine floats.

Before you ditch the trainer, use it to master the rudder. I've been trying.... the rudder will do some pretty cool stuff.