Zyzyx is a big liar... In the James' 3rd mission, he tells that ''The mighty Taurock is expecially good at destroying manaliths.'' And guess what? TAUROCK SUCKS AT DESTROYING MANALITHS! Try for yourselfs. I'll go with the Troll...

I hold up the Dragon as the best possible monster for destroying manaliths. Ents are also good. Jabberockies might work, but they're so bleeding slow that you could probably destroy the manalith BY YOURSELF in the time it takes for one of them to walk from your altar to your target.

Yeah, Dragon rly kicks the ass out of manaliths. Just 2 hits and you're done. They are awesome wizard killers, except in groups. (In groups they SUCK! They just fly circle)

I don't recall that - but if they do then just break them down into smaller control groups - if your attacking with a swarm of dragons chances are they are the main bulk of your army anyway (unless your playing with a lot of souls) so you should have the control groups spare to allow such control.
A really ifine art would be to sit at range and then cycle through the dragons and each time one gets hurt badly pull it out - heal and then send it back in. Though I suspect this "ideal" tactic might not be that feasable ingame unless you are in a very defended position.