Helper skill for nukers?

[microcosm]

I'm lvl 21, and I have lvl 18 ice mastery, lvl 14 fire mastery (not enough sp), lvl 18 lightning mastery, and lvl 19 heuksal mastery.
With the new alchemy, I'm not sure if I should keep up the ice mastery, or should I delevel ice completely and go instead for bicheon?
Ice or Bicheon?
Help please.
btw i have lvl 1 ice imbue, lvl 5 weak guard of ice, lvl 1 ice wall, lvl 1 cold wave - arrest, and lvl 1 ice passive.
also, im a hybrid nuker, and i have about 86% mag. balance.

[Irukandji]

ice is still good for the defence - and you don't want another weapon mastery, unless your planning to farm a lot of sp.

[Luye]

the frost nova series will save ur butt sometimes when too many monsters aggro you, don't get bicheon if your using heuksal