Ever thought about just letting the sage/sorc go and taking your team of 4-5 people to go complete a PvP objective?
The best part about force speed is that, when properly used, you can entice 4-5 people to chase you around while the rest of your team.... WINS THE GAME.
Seriously, the first thing you did wrong in PvP was get tunnel vision trying to kill one Sage/sorc. Let them run, they are taking them selves out of the fight giving you and your 4 buddies an opportunity to get back to the actual match.
There is no aspect/ability of SWTOR PvP that is so OP that it negates good tactics. If your a good player you can play ANY class well. L2P.