I am playing my first character and I intended to be a pure 2h melee. Went for 132 2h 104 crossbow at last.
Why did i do this? If you play any of the camping maps while defending, and you are only melee, you have to wait 2-3 minutes to do actually something. With a crossbow, I can fire to players going alone, or at least shoot 2 quarrels while the whole enemy charges and then switch to my 2h. Otherwise I do nothing.
Also, I suck at blocking, seriously. I am trying to improve, but while improving I don't want to be unuseful to my team, so I usually go into "support mode", trying to shoot with my xbow if i can (meaning there's no way I do FF) or going to help someone fighting in 1vs1 situation with my 2h. When I fight myself a 1 vs 1 I die most of the time. So even if I want to be a melee player, my ranged skills are usually more useful (specially if there is no cooperation from the team).
Even doing this, I almost never kill people with the xbow, I usually hit 1 player in the charge (firing 2-3 quarrels) and then I go melee or stay with the crossbow depending on the circumstances.
When my team is attacking, and there are archers at rooftops and such, I usually try to aim for them. If they don't see me/ fire at me I stay ranged, otherwise I go melee and look for some cover.
In addition to all this, it is very effective for cavalry. It doesn't usually save you from lance cavalry, but if there are HA and your team got none, that way I can do something.
I am not trying to say it should be nerfed (it probably needs more wpf requirement to be useful), just trying to explain why I (a noob in this game) am using it right now. And it's not because it does a lot of damage or its OP, its because is useful (specially since I suck at melee) and it's not as boring as going pure melee.
In my clan, we have some melee/crossbow hybrids infantry. Since we don't use shields, we have more weight free, we shouldn't be the first at charge... So I guess bringing a crossbow is quite rational.