Actually i made a suggestion in an odd hour to this problem so it just gone away unseen.
The summary is, we remove roles in their current form altogether and make alternative variants on all heroes so they can be used in any needed way.
I believe atleast half of the current heroes are well capatable of becoming tank/dps/support separately when needed so people no longer get locked out of cool heroes because they have to play support or whatever. Just choose what you want and fill in the role after it.
The second alternative is atleast doubling the amount of support and tank classes because they are simply not enough to make role quene in a way that its tolerable.