I dont have a mathematical answer but I know that DS are really good at bossing, and about to get a buff.
NW are about to be pretty good with revamp
I love my avenger! but im usually a loner on that...
At max damage? Dit, it'll probably cost you a mansion or something since you need like 20-30m range to cap all the time with the right skills.
Everyone else just depends on the funding you put into it or what you want the class to do really....
those are some of the best bossers imo. mech is a good bosser against bosses that arent or cannot move against moving bosses they are terrible.