Broken means the class is impossible to play effectively, which is obviously not the case. To say that the class is broken because it is more difficult to play than other classes is ridiculous. No one is forcing you to play sentinel, no one is even forcing you to play the game. If you dont like it dont play it. You aren't the target market for the class. I suppose people have every right to petition for making the class easier to play, but honestly to do that without making the class overpowered is a difficult proposition that would more then likely exacerbate any current balance issues.
To the OP I disagree about a few things. Yes Huttball can be very frustrating for sentinels; however, your usefullness in Huttball comes less from your class abilities and more from your knowlege of positioning. If you know when to pass, can be in a position to receive, and use trancendance at the appropriate times, you will be significantly more useful to your team on offense than the players farming for medals. On defense, granted, we dont have the KB ability, but we've got a great snare, and we can kill the ball carrier just as fast as anyone.
I don't think the class needs a KB. There is already a ton of CC in this game and I dont think adding more is the right answer. If anything decrease the cooldown on resolute or give the option of decreasing as part of a skill tree ability, but honestly, a well played sentinel is as capable, effective, and rewarding as any other class without any changes. The fact that you see bad sentinels out there is a testament to the skill it takes to be a good one, and thats what balances out the painful aspects of the class. I dont profess to be an amazing sentinel, but I see the possibility and I'm working at it.