If you are looking for another "KotOR" style game, "Diablo III" may not be the right game for you. Depending on how they advance their game engine and technique, Blizzard may not be interested in making an RPG similar to "KotOR", "VtM: Bloodlines", or "NWN". It all depends on if you want a different kind of RPG experience. If you are looking for a new way to play RPGs, I definately suggest you try out the series at least once. "Diablo" is still a type of RPG, but not in the traditional sense.
R.I.P. to 'The Source' and 'MacCorp'