In a straight up firefight Titans are just as good as any class. Their weakness is in their supers and how they compare tactically to the other classes. While the Fist of Havoc is opportunistic - i.e. you must have the enemy grouped together to get more than one kill and it can be challenging to aim - both the Warlock and the Hunter have supers that are mobile. They can activate them and then roam looking for targets. This is especially true for bladedancing Hunters, as bladedancer gives you a lot of speed and mobility (they can practically fly). You're correct that the Striker really seems to end up being used defensively (a la "The Fist of Panic") and the Defender is at a real disadvantage since most if not all of the other supers can take out both the bubble and you within just one activation. You're also correct that titans are the minority in Crucible. If you check out your grimoire and your kills for each class in the crucible, I'll bet that titans killed in the crucible is the lowest number. Now, if it sounds like I'm busting on Titans a bit, I'm not. I run ONLY titans (I had all 3 at 29/30 prior to TDB but didn't enjoy the other two) and my team of 3 Titans went flawless in ToO yesterday. Since you generally only get one super during a round of ToO, I think that this supports my opening statement. In any case, your choices are to hang in there, and pair up with other classes so that your fireteam is more versatile - or do what many others do and spin up a second class as a warlock or hunter and run that in crucible.