This would be cool in a way, but me personally I hate when people eat clock the whole game. A ranked game online is only 5 min quarters but the play clock is 40 seconds. Some people abuse this and make the game boring in my opinion. You can eat up a whole quarter with 7 plays.
I would rather have them make the playclock stop when your picking a play (have 20 seconds to pick a play)(with an option to keep the same personnel in to save a few seconds), Once you pick a play give you about 20 seconds to get your subs in and snap the ball. That would be the way I would like to see it implemented.