@someone in the forums said:
Other professions, have a (this) role, (that) role, etc.
It is this sentiment, and the fact that devs respond to it that is probably ruining this game's ability to be balanced.
Every class should NOT be able to do every role.
As a matter of fact, there should be roles that each class is explicitly excluded from to eliminate confusion.
Edit: Furthermore, reduce roles for each class to 2 max, depending on game mode it can be slightly more flexible at a dear cost to efficacy.
Soon™ ( ͡° ͜ʖ ͡°) nom nom nom🥔