Good answers in the topic. If I’d emphasize on something it would be:
1) More points in ES, you need to have 92-93% so that you don’t have to worry about life bulb and res at all. DROP THE SPIRIT. This is 100 points in energy saved. ES sorc should not have stats in vita, period.
2) Yes, you don’t need mf. Nova sorc farm bases and HRs as already pointed out.
3) You don’t need sunder, you will kill light immunes groups perfectly fine and if not, they’re worth skipping. Instead, get light skiller, get more dmg and greater ES level.
If this is HC and you have survivability issues, get 2sorc 90+mana amulet and switch to frostburns. You’ll have 63fc bp (griff, arach, viper), but shitload of mana.