If you are wanting dps meters so bad, how about they just set up a training station some where in the universe where you could go and try out your rotations on dummies like in WOW and see how to maximize your dps capabilities. But the side part of that is that the DPS meter would not work outside of that center so you could not compare or use it to hender people from being able to join for flashpoints or multi-player instances.
No need for interrupts, you can see them. No need for avoidable dmg, you can see it. No need for healing meters, because they usually don't tell you anything when plainly looking at HPS. And I don't expect to be able to analyse data of a whole fight to find healspikes and so on.
Endgame on hardmode and nightmare (and even HC Flashpoints without gear) is heavily DPS based. If you fail to execute a correct rotation -> enrage -> wipe. I can't say that this is fun for anybody.
And whoever is crying because of DPS checks: Not needed for HC flashpoints or normal operations. And if they still demand it, don't even bother joining