I get your point about not vetoing things. I don't for regular dungoneering either, because I love the "make the best of what you get" approach to DD. But the Triple Quest is a different, specific set of constraints. The Agnostic's Collar is exhibit A: there's only one altar per level, so a shop that stocks it is a shop that might have sold you Platemail or a Balanced Dagger or a Dragon Soul.
The idea of taking the Vampiric Blade into 3-3 had never occurred to me. I had vetoed it because it offends GG, but as a paladin you can kind of get away with offending GG, and it sure would be nice with resist stacking. Hm.
I had similarly written off the Venom Dagger because although it's, as you note, fine in 3-2, it's offensive to GG in 3-3. Money is so tight that I try not to invest in things that won't be useful across both 3-2 and 3-3. If you're already offending him with blood magic, though, might as well go all the way with poison.

At any rate, good luck and good hunting! You definitely have different strategy ideas than I was using, which is not surprising; a lot of the veter1ans here seem to have very different styles. I would love to see the report of a bloodsword-wielding paladin finishing off 3-3.