The only thing wrong is the 99% shield lasting about half or more of the time a 1v1 takes place. I am a sniper, i also play a smuggler, n a few other classes, agents do well against marauders. Most classes seem to have a counter class. If your a good player you can overcome. This game is one of the most balanced games ive ever played.
The reason people complain so much is usually because they are the players that only pvp and thats all they do, if thats all i did, i wouldve quit this game along time ago, your only playing 25% of this game,.
Mara/sents is PVP classes, they are not that good in PVE mate. Melee dps have always been a weak link in MMORPG and the whole strenght of MARA/Sents lies with PVP. They are just like how Assassins was in GW, pretty mediocre in PVE because they were meant for 1v1 DPS stacking situations in PVP
Also when you get to 50 PVP is pretty much the only thing you can do and when you have played through the game once it's far more fun to level through PVP/Space missions then doing the same sidequests over again. SWTORS problem is that there is not that you go through the same areas each playthrough but that there is too few sidequests.
If they wanted that ppl should do alting then they should have had skipped all VO ffor sidequests and made several sidequests hubs on each planets so you never had to do the same sidequest more then once if you wanted to.
VO for the class stories are awesome but for the sidequests it's pointless.