Why should dps get a special treatment?
You can already see if your tank is bad or your healer is bad, I see absolutely no reason why we shouldn't be allowed to see how the dps perform.

If a offtank fails 3x in a row at spotting the second hand in A3 or failing at the tank swap in Bis Ex or losing hate, because he's not doing hate-combo or a healer is not healing... you gonna replace them sooner or later.
But if one or two of the four dps are bad you have to disband the whole group if you're failing?!