Basically I think levels and experience systems set up unduly artificial milestones for the player to reach and always end up as a grindfest.
The problem is, that there is not a problem at all.
The only problem I see is, that games try to satisfy everyone at once. But the truth is, there are lot of people who like unduly artifical milestones, level and exp, and there're lot of people who dislike it. The same can be said about grinding, class-vs-skill based system, gear-vs-attribute based system etc. etc.
My critique about this counter-design paradigma is, that people tend to design anti-pattern of existing design pattern, instead of designing something fresh, purely inspired. And yes, there's a difference between 'I want to design something which is a counter to something existing' and 'I want to design something which I really like to play', even if the latter comprised old design.