I like striker in PvP more than any other subclass. It's just fun to smash a grouped up enemies, or to shoulder charge someone around a corner.
Granted I don't even try to play at a competitive level and I don't "tryhard" or anything like that.
A lot of it has to do with risk/reward.
Striker is very risky, and at high level play you'll get snipes out of a smash before it lands, so it gets relegated to an "I win" in 1v1.
Also to take shoulder charge you lose the perk that gives you damage reduction during a smash (unless you're wearing one of the helms that gives it).
Also, shoulder charge gets countered very effectively by a shotgun, so it usually comes down to whoever has the better connection.
Compare a smash to a warlock bomb, basically the same effect, except one is ranged and much more likely be effective.