Otis and my player-created human fighter have only a 20' move, even when not encumbered. Is there any other reason for this restriction other than encumbrance, and if so how do I shed it?
If you are wearing heavy or medium armor this will reduce your movement rate from 30 to 20 (or 20 15 for halflings and gnomes). This is one of the reasons its generally okay let your heavy armored characters be medium encumbered (there is no additional penalty).