It's actually the only objectivly debatable point. If certain comps were unable to complete content they'd require adjustments from the devs. Content must be able to be completed regardless of the party composition - that's the baseline. Every adjustment beyond that is (imho pointless) catering to community made problems.
Most people tend to take the route of least resistance, which is bad. But this is not a thing that can be solved(or even should be solved), as every change will just cause an uproar of those who feel disadvantaged, creating a pointless circle of changes and uproars.