Honestly bud its all about play style like when I first started destiny my main was a Titan sometimes I was great in crucible others I completely got slaughtered it really just depends on the day but now I mainly play my warlock and I seem to do better with my sunsinger but that's just my opinion also with crucible you have to completely change up your set up in comparison to PvE because the thing that work for you in PvE more often than not will fail in the crucible so set up your abilities and loadout to match your pace and play style and with some luck you should do fine I myself highly recommend using invective if you have it