Here is the problem
Fire + lightning + cold + heuksal + bicheon = too much masteries (and insane SP need)
Bicheon skills are very nice for 1vs1. IMO for serious pvp, you have to get either spear skills or sword skills to get the 'unabling' effects (knockdown/stun/knockback). But for war or group pvp nuking only can be enough.
If you want to use nukes only, max your ghostwalk and use it a lot in pvp to escape and nuke again.
I don't understand about the imbue ? you don't use it ? It works with nukes you know, it increases damages a lot.