Keep the regen bp, dump the other +wisdom items anyhow. Mana pool doesn't impact exp at all over time, because how much damage you deal relies so much more on your capability to regain mana. Regen bp helps you Cannibalize more efficiently, and make more exp over time.
Ferrealz, I would ignore the "Wisdom" statistic in Everquest, as a shaman. I levelled to ... 63? 64? before passing 150 wisdom, and never missed it. Obviously I have a much bigger mana pool now, but it's mostly useful just in raid encounters (whose loot also boosted it so high). For exp, what I'm casting is governed by how fast mana comes back, not how much there is sitting waiting.