Ideally, I'd want more plays and formation to be more viable. Some things are just vastly overpowered and I'm sure jdb is working on ways to even out the playing field - or we've simply just discovered how to get the most out of specific plays.
I've only played one league and I've made a sport out of making it as hard as possible to gameplan against me, by constantly utilizing as many plays from the same formations as possible, meaning I limit myself to say 4 formations on offense. I've then tried out various plays from those formations and ended with what I think is a rather balanced playbook. I've also realized, that many of the "better players" aren't in the playbook I have available, but I'll make do.
A while back, I suggested that we should be able to help development by making plays ourselves. Plays that should either be approved by jdb (to avoid "perfect" plays to abuse the game engine) or have X amount of approve votes from a group of selected users, who has a history of helping MFN develop (like setherick or raymattison and others in MFN1. I'm sure others can drop names better than I can).
One thing that I really want to help, is fleshing out the formations with less plays. In some formations, you have maybe 1 play for inside/outside run or medium pass. All formations should be more viable and varied so it's easier to play in different ways.
For now, I'll stick to my method. It includes FL Hitch, but just because it works well, I'm not going to remove it from my playbook. I won't do like some of the more veteran GM's and limit my playbook to 8-15 plays either though. That just seems wrong and overuse penalty should incur much faster. Not that I want to see more sacks or drops (which is typically what happens), but just see defenses react better to offensive overuse.
I think nothing is wrong with using a specifc play or two, to punch the ball in if you're close to the goal line, but when you can dominate games with only using 10 plays and not really care about overuse, I think something's wrong.
Last: I think you could help yourself and your case by having a better subject title and maybe flesh out a bit what you hope to accomplish.
Also this is not a league forum, but general forum.
Good luck mate. :-)