Completely disregarding the system before it's managed to really exist very long is just the hyperbolic nonsense that plagues almost all discussion about MMOs. DPS who talks or explains things is going to be more likely to have their name clicked than a silent tank or healer.

One issue with it is you can't commendate someone if they leave the dungeon at the end. What's the point of that? Is there some big fear of AFK'ers receiving commendations or something?

I'll say I don't necessarily like the system as it is. I thought it would be it would be something optional, rather than a guided system. That gives it a lot better value than "Hey commend someone quick" at the end of every dungeon. It'd be nice to see some context on why the person is being commended as well. I understand it's a pretty simple system, but maybe that will work out in the end. Just be polite and slightly social and you'll probably get commendations, I don't think it's very complex.