Guess that depends on whether you believe peppers will throw roots out of the stem as tomatoes do. :)

For tomatoes, I do just that; take off bottom leaves and continue filling up the pot to the rim as needed. For peppers, I would generally repot if I was certain that it was root bound. That said, I freely plant them deeper when transplanting, believing they will root if I take off bottom leaves -- cotyledons or first leaves. Never really checked to see if they did, though, but it's never adversely affected my plants either. By the end of the season, my pots are full of roots, even on the top if I use 5 gallons or less, but I'm not positive the roots at the top came from the upper stem.

In Florida, though, I think I would repot the big guys. You have a considerable number of growing months left, right? That said, repotting would probably stress the plant more than filling with soil to the top, so....

If they're doing OK, just leave'em alone, and put some mulch on top. In my experience, a 2-3' plant shouldn't be root bound in a five gallon pot until the end of the season and it's 4-5' tall. If it ain't broke, don't fix it...

If you have 5 gallon pots, then your plants should be fine. But, having the soil line 5" below the top of the pot is likely giving away a couple gallons of soil. Adding soil to the top would probably be the easiest way to add soil but I don't think that would benefit the plants much. They can and probably will add roots below the new soil line but at this point, it is a bit late for that. I would carefully try to lift the plant out of the pot, add soil to the bottom and some to the sides and put it back. Too much trauma will cause the plant to go into transplant shock and slow down production for a while until it readjusts. If you don't feel confident that you can do that without traumatizing the plants, then I would add a couple inches to the top and be done with it.