Yeah, agreed. Personally, even playing as DPS, I find it hard to have a reason to give commendations to DPS. I... I don't know how much one is actually contributing, since - for the most part and commonly - there are no DPS meters to look at. In any given dungeon I run, I could be doing 99% of the DPS, 1% of the DPS, or it could be any split in-between. Did the run feel slow? I dunno, it's my first time through for most of these places. Even in the future, if the run is five minutes longer or shorter, there's really no way to chalk that up to 'awesome DPS' unless we refer back to those pesky meters I mentioned.
The tank or heals doing their job satisfactorily is obvious to the whole group; a DPS doing their job means, what, the duty completion time was acceptable? The completion time was quick? We're already finishing with 75 or 85 minutes left on that timer. It's difficult to quantify.
It's a cool system, I suppose, but it's a bit broke. I've begun to give commendations to DPS solely because they are, in fact, DPS, and I know how much less frequently they'll get commendations.
Plus, and I know I am still leveling up, but folks just bail straight out of the instance before I can even hit ESC and skip a cutscene... and if I want to look at the loot and do rolls first, then forget it. Everyone else is gone by the time I click 'greed' on two greens.
I think it would be cool if I could possibly think for two seconds about who deserves it, then hand it out regardless of whether the person exited the instance or not.