I agree GM weapons and GM resist makes fights last much longer. Even a force hally makes a big difference, IMO. a 10+ force can insta-kill while a GM usually can't.Personally, the plus side of this to me is that most people actually use vanqs in fights. With our current knowledge and understanding of mechanics, GM-vs-GM weapon fights would last a lot longer.
Tank mages are supposed to be able to insta kill, the problem though is that right now we have the cycle timer inaccuracy which makes vanqs better than they are because you can keep spamming hally for high DPS and no mana cost. But that will get fixed next patch anyway.
I think magic weapon drops are very balanced, I don't find that many powers or vanqs at all. And there's always the chance of getting too many broadswords just like t2a off daemons, doesn't seem that bad.