In my opinion, these skills are pretty lame.. and add nothing to a class's functionality ;/
Slow poison
Truly lame.. temporarily stops the HP drain from poison but not the DEF drop, while poison is easily cured by a green herb, panacea, royal jelly or a green pot.. all which are cheap.
Talkie Box
Adds nothing to the functionality of a sniper
Signum Crisis
Waste of skill points, I can't really see a use for dropping a demon/undead monsters def because that's just too much trouble for leveling.. and out of the question for MvPing
Mana Recharge
Because it needs mace mastery level 10, lol wut.
Gravitational Field
If only grav field did not prevent you from moving, this skill could arguably be 'decent' right now its a pretty stupid skill and I can't seem to find a use for it (nothing that heavens drive can fix)
Magical bullet
Waste of coins, does bad damage, ghost property.. can't find a use for this
edit:
Adaption to Circumstances
It's a requirement for encore > musical lesson but if it wasn't this skill would be really useless.
So yea, if anyone else thinks a skill is pretty bad and adds nothing to the functionality of a class, postt.