NEVER LEVEL YOUR SPEAR SKILLS PAST LEVEL 1!!!!!!
This couldn't be more important. Spear abilities like Wolf Bite, Dancing Demon, Ghost and Soul Spear, etc will only do increased damage for STR users. If you are a nuker, just get level 1 in the spear skills and no more. Also, the Bloody Fan or whatever it is is useless, dont even get level one in it.
This of course does not apply to the spear HP passive, which you should level to as high as possible.
If you are planning on a nuker, your should avoid Force. It's up to you, but nukers are about damage not spoony healing and such.

But, since you have already put some skills into it, I would recommend that you go 90 Fire, 85 Lightning, at LEAST 60 in Spear, and whatever else you want into Force. Anything more would waste your mastery points.
Do read that guide by RaiKiRii, it is very well written. I got most of my information from his guide! I am planning on being a 90/85/65/60 Fire/Light/Cold/Spear nuker when I grow up. =)