"Action combat" nowadays is a trend invented by some PR guy eagered to call "old-gen" MMO combat "tedious and too much complicated" where standing still doing your best skill rotation is "lame and not rewarding". That's why you have dodge, sprint, telegraphs and active positioning / aiming. It doesn't reinvent the wheel at all, it just add more wheels. In most of these new "action combat" MMO (TERA, Secret World, GW2, etc) they force you to be "more mobile and engaged", you have to aim you skills, dodge some, prevent the opponents' attacks and whatnot.
The pros are : gameplay feels much dynamic and engaging, rather than sitting on your ass rotating your flavor spells like a chain robot you have to move, dodge, aim and shit. You have to learn about what other classe can do.
The cons are : it doesn't reinvent anything and it limits choices, in WoW having a 20? skills action bar is okay because you have a lot of utility / class skills. On the other hand, in these "action combat" games your action bar skills setup is limited (most of the time 10- skills), they say you have to "choose what skills you're gonna play" on the fly and skills are class / faction shared to the bone. You lack diversity, classes are mirrored most of the time.
I'm not gonna say anything about Wildstar's current beta state for obvious reasons (you can check that on many other websites), but people need to know the game doesn't have a release date, so any attempt at defining how the game will be at launch is wild assumptions at best. A lot of MMO productions made critical changes before launch, and stating Wildstar won't is nothing but guessing.
