All classes are viable at pvp and pve, so you just go ahead and play whatever class you want to play. If you enjoy paladin in WoW I'll bet you'll enjoy the commando more than the sentinel due to the fact that you can be a healer & a damage dealer from afar (err 30m) whereas the sentinel is mainly a damage dealer up in your face. Just grab field respec and enjoy being super versatile in your role as a commando.
Personally I'm sick of all the jedi / sith bullcrap, so I roll with guns only, and the commando has a big f****** gun to boot and it looks awesome.