I play all 3 classes and i must say the titan is the easiest in the crucible imo. I run striker with: max agility/armor, aftermath, lightning grenades, ability that lets grenades and aftermath last longer, and armamentarium. My armor is also set for max intellect and discipline. Double lightning grenades are amazing at area denial and i rack up a ton of assists as well (while not so mlg assists help alot). However FOH can be tricky sometimes cause of how close you have to get. I do agree 100% on titan melee. Might as well not even be an option. Overall all though i love my titan in crucible and also have my highest k/d's. As far as the bubble is concerned, i never run the bubble. Although i have been on teams with 2-3 bubble titans in iron banner and have just wrecked because you can get a ton of orbs. The bubble is a support class. You defend a crucial capture point or your teamates, or you make orbs for your teamates to wreak havoc. It will be hard to do something with that class cause its a support class not an offensive class. As far as support goes bubble titans excel.