Yeah, that's kind of my problem with Shaman as well. Canni always annoyed the shit out of me. The buffs thing I'm not as worried about, since I have no problem telling people to fuck off if they want something stupid like agi, but I did the SK/Shaman thing on Selo's and found the Shaman to be kind of a PITA. It wasn't quite as bad when I was just duoing (like you said, dot mana cost is high, always casting, etc.), but it became so annoying grouping with him that I eventually just swapped him to a Bard.
Well, that helps. Down to enchanter or mage, I guess. I know mage is going to be the "simpler" choice, especially grouped, but enchanter just seems like it offers a ton to a Paladin, especially when it comes to duoing dungeons and tougher named. I feel like I'd be mostly relegated to duoing outdoor stuff on the Mage or expansions old content.