I personally expect KOTOR III to deviate strongly from the previous two games. Rather than the usual quasi-realtime RPG, it will instead take the form of a side-scrolling beat 'em up (or slash em' up, or whatever term you'd apply to wanton lightsabre combat). You will first be taken to a classic character select screen where up to two players may decide (or fight over) whether to play as Revan or the Exile, then proceed on a badass romp through the streets of the oldskool Sith Empire, Jedi style. The typical classical musical score will be replaced with hardcore techno and breakbeat, and through slicing up objects in the FULLY DESTRUCTIBLE ENVIRONMENTS, players will be able to find handy kolto canisters and midichlorian sundaes with which to replenish their health and force points, respectively.
But in all seriousness, I'd like to see KOTOR III handled in a similar fashion to the Neverwinter Nights trilogy, in that rather than featuring a new story with new characters, it would go on to show the culmination of the events of the previous two games in an "Epic Level" scenario. Since the Exile presumably left to follow Revan at the end of the second game, I imagine that they would meet up, introducing the possibility of two player-made characters in a single game, which would be a first. Perhaps, if a new party system were introduced, they would travel together, or perhaps they would split up, with the game switching between each of their paths. This in turn would give the option of numerous endings; would they both adhere to the Jedi code? Would one fall while the other remained in the light? Or would they both give in to the dark side?
Regardless of whether or not this is where the game ends up going, I don't think there's anyone out there who wouldn't want to take both their carefully crafted characters, Revan and the Exile, levelled up to the point of godhood, and tear up the galaxy. Because I certainly would.
