My front speakers my surroundsound speakers and my center channel are all full range speakers. I thought it was maximizing their potential. Is there a reason I wouldn’t want to do this?
What speakers are we talking about? What sub(s)? Can your speakers truly compete with your sub(s)?
The whole reason of having a sub(s) is to use it. If you only want it for only LFE in movies rather than supplementing your speakers in general just set them all to large (which it sounds like you did), but you were the one questioning the use of the sub when (assuming) you're expanding 2.0 into surround with PL so now I'm not sure what you want your setup to handle. If you set all your speakers to large the only time you'll have your sub in use is for programming with a recorded LFE channel (.1). Expand on what you want to happen when....
FWIW I have "full range" speakers and I still use subs for better handling of (and positioning for) bass. My subs are much better than my what-many-might-consider full range speakers at probably anything below 200hz plus they're better positioned for better response throughout the room. I don't cross them there, tho I do cross them at 100hz and sometimes more.