And that is pretty much the problem. You do know that a Warrior can 1v1 any class in WoW right? If the player is really good. ToR has too much "you need 2 more ppl to lock down and kill this class" and that kind of gameplay works wonders in games like MOBAS for instance but in a game that has constant PVP it just becomes very frustrating very quickly.
IF yo n eed more then 1 player to lock down 1 class then there is something wrong with balance. Damage output is just not balanced at all in TOR.
It's another thng altogheter if you are up against 1 player that is simply just leagues more experienced then you and better at PVPing but when a class has so much utility and is on it's core so good that it can't be countered unles you have 2 ppl focusing down the target then there is somethign wrong. Add Force camo to the mix with Guided by the force and you have real issues in the balancing part because not only do you not have to 1v1 the class but you also have to let them not escape or they will regen their HP.
Buff other classes, but first rework whole PVP
ToR's classes was certainly made for PVE only and then they slapped PVP on as a last thing before release. You just have too many classes that "does the same thing but either better or worse" in ToR and it's just hard to balance a PVP game around that many sub classes and talent trees. They should have kept it more simple.
If Sent/Mara are rock, then Agent is paper. If they catch a Sent out of stealth and stun them, they are going to die 90% of the time.
Sents are not invicible, just learn to play your class better.