lvl 27 titan, not the best but i'm not too bad (1.7ish kdr), and striker is definitely viable in the crucible. With Shoulder charge, Transfusion and highest defence the titan is one of the best classes at melee, and fist of havoc is one of the better supers. With the exotic helmet that ads more bonuses to fist of havoc it is also versatile. The grenades are decent, with the 3rd giving good crowed control and flash bang always being viable. You can come out ahead in many even range fights because of extra armour, and the lack of agility not making much of a difference with shoulder charge + good positioning. Transfusion and the recovery codex gives a nice amount of recovery as well. In a way the class feels like it's designed for PvP, if you're" failing" with it you're either not playing it correctly or not as good of a player as you expect.