This whole thread is silly.
Firstly there is a reason leaderboards are class specific. Its not feasible nor reasonable to have EVERY class equal. Its just not how it works and honestly every game and every genera struggles with this. Blizzard knows this thats why the leaderboard's are separate. Now I could understand you being upset or annoyed if the monk or barb is directly competing with wizards etc but thats just not the case even in groups.
I remember a time when barbs had been OP as well as monks. This is true for EVERY class in the game. Every class has been strong at one time or another.
You're complaining that you are "forced to play support in the meta". I dont know where to even start with this statement. You are not forced to play anything. Firstly if you want to play damage do so, i also hope you are sitting down for this, you can also play a dps monk/barb in a group! As mentioned you can level and gear a character in like an hour if you have some friends, which i assume you do if you want to play in a group. I have most of the classes leveled and able to run GR60+ in less than an hour. If you aint enjoying playing your class, dont. If your group is forcing you to play support monk or barb dont play with them if its spoiling your enjoyment of the game.
I just facepalm everytime is see one of these topics rise concerning diablo. Its just silly. Even when i used to play WoW and warriors for example would complain about not being able to do damage in raids being forced to tank. Its their role, its their main purpose, if you aint interested in doing that dont play that class.