From my experience so far, there aren't many hot keyed skills, more than just many different inputs for different abilities. The fighting is basically like MMO Tekken, where different combinations of Left Click, Right Click, and WASD use different skills as you unlock them with the usual skill points. If I wanted to make my warrior do I spinning slash to the left, just "A" and left click, but for other special skills, it may be to hold Shift, or Q and right click, etc.
It's nothing too special, but it feels fluid. Grinding can be very boring in an MMO, but the combat itself feels very fluid and looks pretty cool, with all the fancy animations and such. Not saying grinding isn't boring in this game, because there's going to be a ton of grinding for sure, but the combat system doesn't get in your way too much.
My tip for grinding so far is to learn your character and playing style. Most of the mobs in BD can be kited easily, or rounded up into large groups and slaughtered if you know your character well. That sense of discovery should let you fight mobs, many levels higher than you and speed up your leveling process if you can manage.
