first of, how do you define a turn-based RPG? granted I wouldn't know the answer...
BTW Kotor is not an ARPG.
An ARPG is an action game with some RPG elements or RPG-like elements. In short any kind of game similar to Secret of Mana or Zelda or Y's or that like.
You can have a standard RPG with realtime/pseudo-realtime combat - see any of the latter Ultima games, Baldur's Gate, Star Ocean, Tales series, Vagrant Story, and now FFXII. The difference is that in ARPGs, you (usually) control one character and perform actions similar to how you would in an action game, but in an RPG with realtime combat, you are still issuing battle commands and controlling a party, you're just doing it in realtime or pseudo-realtime (where you can pause to issue commands).