Yep, keep it single-player. A 2-player pazaak game might be fun, but I'd prefer to have a good single player game. Going from 1 player in K1/2 to MP for K3 would be a bit disappointing--it just wouldn't play the same.
Vlad--it's possible to socialize in a single player game, but it's a different kind of interaction (and I understand your point on games being a social activity). My son and I play together--he makes the choices, I do the mechanics (since it's my laptop we play on) and the math puzzles that he's too young to do. We get to laugh at HK's comments and talk about the choices he's making and how it could affect his character. Hubby and I end up chatting about how we fought x Boss, or how we handled a particular sidequest, what planet was best, what lightsaber upgrades work best in a given situation, etc. Granted, we're not physically playing at the exact same time against or with each other, so it's not quite the same as in an MP game, but nevertheless we've made it work. So, while it's a SP game, we've gotten some good socializing going on in our family, and I'd argue that all of us posting on the forum are socializing quite a bit. When my family wants to all play the same game at the same time, we pull out the board games and play Life or Mousetrap or Monopoly or something like that. Kotor's just a nice alternative and a very fun SP RPG, and I'd like them to keep as much of the framework as possible for K3.