Well, I am less of an alt-itis type of person than most. And (annoyingly) I become attached to my characters. It actually took me a long time to decide to replace just one of my mages. Considering the time investment necessary to remake all of my macros I'd have to see significant advantages to justify the time it would take to get a new toon to 80 (not doing RAF, nor going to spend the money to do RAF).

Heck, just changing my talent specs is going to take a lot of configuration. I truly wish there was an easier way to do all this!

I currently have 1 level 30ish shaman. Can't say I'm too thrilled with their mechanics. Theorycraft-wise and evidence from others shows that they are pretty much the best all around Healer/DPS class - but replacing toons isn't what I'm looking for. More of a "given these toons, with maybe one mage turning into a warlock how would you guys pick the talents".

As for Off-Tank - the warlock offers an in-combat res (and my skills are poor enough that I like that) and pet tanks where pretty uber when I left WoW against bosses that did lots of AOE damage (since they only take 10% of damage). Not sure if that is still the case, but it sure helped. Oh, and OT can be considered another form of CC that works just about every time.