I played a minion Witch in hardcore up to level 71. Died. But continued on to level 76, iirc, by the last day.
Was able to solo every endgame Map, any mods sans blood magic up to level 68.
My core build was:
http://www.pathofexile.com/passive-s...0Qf8ae1YGydVgb
@ level 60. The new chaos resist talents didn't exist at the time. Once the core build is filled you are free to spec into ANY element or alternate path you like; more defense, physical dps wand, elemental wands, full support, melee summoner, knife & fork, dual totem, frost totems, wand totems, etc. Anything works after the core is filled out.
I personally used lightning + max cast speed as it was the highest elemental damage possible at the time. However, I did respec the build a few times to see if it worked with wands [both elemental and physical], cold damage and dual totems. No difficulty with any combination in solo or group endgame play.