Oops, you are right. I recant! I guess this means if you're using haste with GC you should have CON = 3 + SPD or something like that.
At least Speed +2. With GC, I normally pump Con until Con=Speed+4, then pump speed until Speed=Con-2, then pump Con again.
But we digress. The thread's original topic is, essentially, complaining about partying with people who use Lone Wolf and/or Glass Cannon. In my opinion, Lone Wolf isn't overpowered at all, but Glass Cannon definitely is, and I could definitely see how co-op with someone using GC, when you don't, could make you very aware of that imbalance, as they get these really long turns doing everything under the sun, while your non-overpowered character feels meek in comparison. Not to mention the whole "same partner every time" feeling.
So yeah, Glass Cannon needs to be beaten with a nerf bat. Obviously. Hopefully that would improve build diversity to the metagame and fix OP's problem.