i haven't played it on teh wii, but you should be able to modify your playbook (although i'm not sure how much you can delete out of it). worst case scenario you can put the plays you want to use all next to each other, or at least put them as the first play or two in the formation, so you don't have to get too far into the playbook to find them.
personally i like having a lot of plays though, and i'll probably run 30-35 different plays on offense and 20-25 different plays on defense each game (and i'm using a 21inch tv)