I agree to a point. However there are at leat 4 play throughs with enough difference to make it woth levelling 4 alts before becoming too repetitive. 2 different starting planets for each faction. I found playing a force user and non force user on both Republic and Empire sides provides enough variety particularly if you don't just play the dark side equivalent of the light side class you already levelled. Or vice versa.
I found the feel, path, plot, mood and experience very different playing
Sorcerer
Guardian
Commando
Sniper
Sure there are some repeated quests but how you complete them and who you complete them with varies.