It's clearly impossible for Blizzard to appropriately balance all of the classes around all of the various possible endgame activities. They struggle enough just with balancing things between arenas and raiding. My experience with my Death Knight over the last few weeks has made me wish that a little bit more attention might be paid to balancing the classes a little more evenly around the casual player that just likes to run the occasional 5 man instance.
Maybe the issue is that I just shouldn't be concerned with dps meters in 5 mans, as long as the dps is good enough and we're getting through everything, why should I care. But it bothers me.
I've been playing my warlock a long time. I would say I'm fairly skilled at playing a destruction warlock in a PvE environment. Even when the talent tree fairy moves things to the point where destruction is significantly behind affliction in theoretical output (as most would argue it is now) I'm still able to get significantly higher DPS out of my destruction spec than I am as affliction. There is a degree of muscle memory and inate understanding of the right things to do at certain times.
So I find it frustrating, that on my death knight - a character that I have played seriously in instances for about 2 weeks, I am not only able to eek out slightly higher dps than my warlock (who is better geared) - I'm able to embarrassingly crush the warlock. It isn't even close. On test dummies, in instances, while AFK in front of the auction house, my death knight is able to generate dps that is about 25% higher than my better geared warlock and massively more practiced.
As a caveat, I'm not talking about an enormous difference in gear levels here - it's about a 400 point different in GearScore and about a 4-5 point difference in average item level. The item level difference is less than you might think given the GearScore difference, but that's because I've still got one PvP item and one tanking item that I'm using on the death knight.
Not sure there is much that could be done about it since balancing things around 5 mans would then likely create offsetting imbalance at the raiding level. But it would sure help my poor warlocks self-esteem.
At least the death knight doesn't bring cookies and crowd control!