Does Cave Spec work for pve? Disease, dot then kite?

if you solo, yes.
If you group, people will remember that you only have green / blue buffs, so next time they'll invite another sham over you, and only resort to you if they don't find a better one (which with i30 in beta is quite impossible)

Just remember that midgard is NOT a realm with a bunch of well organized and dense monster camps to aedot and kite.
So you'll have to cast quite a bit of diseases before you'll get the pbaoe disease to run in camps, squeeze it, collect many, turn and run, then aedot and start kiting

Just spec for buffs n heals on the way up and find the biggest tank class you can:)

You plus a higher lv zerk or savage makes for a good combo:)