While combat will seem fairly similar to what you expect from WoW (or, frankly, Everquest before it), there are a few nice changes and other enhancements here and there. Quest objectives are highlighted on both your big map and minimap, loot-able corpses show a pillar of light that's color coded for any better-than-common items that can be picked up, and characters have solid animations for moving and firing (and yes, you can fire on the move!) that give some battles a more action-oriented feel. For example, even low-level Republic Troopers can charge in with rifle blazing, fire off an explosive shell when closing in to melee range, then finish off the fight by smashing the enemy's face with the butt of the rifle - all with three keypresses. For some classes, there seems to be a focus on being able to stay mobile where you don't have to stop and channel a spell or slowly aim a weapon, (Swtor Credits)and while that certainly will have gameplay implications (especially in PvP), for now it makes things feel more like Star Wars.
The lightsabers help make the whole thing feel more authentic as well, although my time spent with the game's low-level introductory areas mostly had me wielding practice weapons and vibroblades - but already there were plenty of acrobatic saber-swinging moves right out of the films as well as the original two Knights games. From Force-using ground smashes to saber defense that include both deflecting blaster fire and blocking enemy melee swings, things look and feel more cinematic than you might expect, even if there's still a fairly simple dice game running just under the surface.
When an enemy projectile is fired at you, you still can't move to dodge it in real time, nor are players of gunslinging classes required to actually aim their weapons; all they have to do is target an enemy and press a key to fire. Simply put, The Old Republic follows the World of Warcraft model of action and combat very closely, and the ranged-attack classes are going to notice it first and foremost. While new mechanics like a couple of classes' ability to hide behind cover add a bit of flavor and strategy,(Swtor Credits) be aware that at best, this is a solid evolution of the generation of MMORPGs started back in 1999 with Everquest. If you're looking for a game to change the way MMOs are played, this ain't it.
