Caster focus, what to do?

[Shumanfoo]

I'm working on a build of a caster focused FvS. I already run a TWF FvS which is obviously focused on buff/dmg with the ability to heal as needed. The characters I like to play most are heal/supporting characters so I've created variations of true Cleric or true FvS on paper. It seems that I really need to pick a spell class to focus on and that's the dilema at the moment. I'm not sure what works better in mid to late game spell casting.

My initial thoughts are that I could choose to focus on Evo, Ench, or Necro as viable. It looks like the benefit of Evo is that the major spells don't have SR and therefor frees up 2 feats. I really like the idea of CC to keep enemies damage down, but it seems a high cost of feats just for command, greater command, and hold person. Never really used necro spells yet so I would need input on how well those work.

I'm leaning toward Evo which would mean the following feats in approximate order:
Tough
SF: Evo (human)
Extend
Empower
Max
GSF: Evo
Heighten
Quicken?

Thanks,
Shu