I still think it sould be usable because there isn't anything a m/r can use that would benefit it in a way other to slow down them down. It takes alot to increase speed for any class and this is just an extra incentive. Take that with the fact tha most m/r will use daggers instead of 2-h staves and they are already at a disadvantage. If the daggers could stack with each other in terms of both p/m damage i could see why it isn't allowed. Too many resrictions for this class. Clear thought would be used over this elite skill anyway so whats the point of having it.
You do realize that you can tier both a wand and dagger for extra mdam, right? No M/R uses two daggers lol, that'd just be stupid. M/R can get the highest mdam of all mages, afaik, by tiering wand/dagger, so I hardly see how that's a "disadvantage."
You get a free
11% cast speed buff, so why exactly would you use Clear Thought over that? There's no need to nitpick over the extra 10% from Clear Thought when all mages can hit the cap of .5 seconds anyway; it won't do you any good during burns.