yeah, sorry but the difference is clear even to me, who surely I'm not here from an year and a half ^^
That's not the problem about one (cheap) tactic destroying an (expensive) one, or a lot of strategies would be unlegit.
This one just has this "feeling of unfairness" and "annoying" nature llamabeast talked about. A mage which comes, casts 2 spells, then goes away - and the spells continues to go on, undispellable, damaging every kind of army. No possibility of a lucky shot, and quite difficult ways to prevent.
I mean, I don't even know why am I arguing about this, it's so clear that all the current MP games decided this is unlegit. So why to defend this, you can't use it anyway, so wouldn't it be better if it gets nerfed down a bit in a way that even makes logic sense? This tactic would become possibly USABLE, why not, with a niche usefulness, adding one more to the many various strategies which make this game rich! Everybody happy
as it is now, nobody can use it anyway