i don't think they do. basically here's what i did. you may be able to try it just one a couple teams.
i turned off xp after 26 so no qb generates any additional xp during the year. younger players still accrue.
set superstar and xfactor to star development as they acrue super fast.
my qb reductions:
-30 DAC
-20 MAC
-10 SAC
from every QB in the game.
Made the best WR's in the game cap out at 88.
that's is basically all i did. i wanted to lower qb because i want more off target throws in the game and wr's felt like they caught a bit too much. it felt like it helped some, but still ratings didn't feel super effected even that low for some reason. ??