Lightning damage witch?

Im still just a lvl 23 witch on hardcore (at least for now), and haven't yet even decided which element to focus on. This is my first time playing the game, so I'm kind of undecided, which way to go...

Firstly, I kindly ask you to tell me whether I have messed something up with my buil already, so my build at the moment is the following:


Secondly, any suggestions how to proceed with this build? Should I choose one element now and go for it, or pick some critical hit boosting skills or what? Which element should I choose? I didn't like the Spark-skill in the beginning, but I just got an arc-skill-gem, and I like it! I kind of like the idea of lightning-oriented witch, but then again, I also use lots of other elements also: Freezing pulse, Ice spear, Fireball and Firestorm. I should probably cut down the number of active offensive skills... So any suggestions how to proceed from here? Which element is the "best"? :P Lots of people seem to favor the cold damage, probably due to its defensive properties...

I kind of played with the skill tree around with lightning damage and critical hits in mind and this is what I ended up with:


Is that build any good? Yeah, I know its very very very late game, and probably I will never have that much skill points to spent, but anyways...

Bump. Any help appreciated! =)