For me Ghost Charges, any kind of other bombs or spending money on healing potions has been a lifesaver for my group.

Also Sisterstones Dawn and Dusk was so good against Undead.

Yeah spellcasters are hit or miss for me. :P I like them here, don't like them in DnD as much.

Only played a Witch Spinner of Threads at lvl 7 at the moment. Absolutely loving it! Focus is on full support. Next char is going to be a Thaumaturge