One thing to consider is having 3 Pure pass focused CB's and 3 Pure Run stopping CB's. Then through proper depth chart setup you can make it so you are more capable of defending the run when you need to, an more capable of defending the pass when you need to, then let them have minimum crossover skills, like the pass guys have 30 or so BRB, and the run guys have 50/50 deflecting and coverage tech, and manipulate the depth chart so they end up where you want against balanced teams.
CB1 and CB4 run focused, CB2 and CB3 pass focused, etc.
ALL of your LB's should be fast, If you want to shut down the run you should have them all hit 80 minimum speed, and then one ROLB with 95+ speed and heavy conditioning, and snap reaction.
In fact, everyone should have 60-70 conditioning on defense except for the D-line which can get away with 50-60 so long as they have 40-60 toughness. Also consider having a S*SS and just using one, or possibly having a S* FS as well, although thats less necessary than an SS because the playbook allows you to do more thigns with the SS position, than the FS position unless you are running an exclusively zone defense.
Other then that, your roster count is fine, unless you start adding S*'s