Archmages - Forever useless at bosses?

The problem is also with the balancing I think. In other versions AM have elemental weapons that deal 25% more damage, and i think onyx apples are rare or non existent in those versions. In GMS there are no elemental weapons and lots of apples.

Those weapons truly aren't needed. Mages can top everyone unbuffed by hitting around 7~8 NEUTRAL enemies, even folks using Onyx Apples.

The problem is that bosses thus far have been driven by single target DPS only. Horntail is a full-fight with multipart, but it's simply not required, and it's too big I think to get the best out of it.

Pink Bean gives a purpose to Mages without giving them a means to match other classes in single target DPS. This is the solution: give them many enemies to knock out with their great AoE (where Mages MUST be used) and give them a method to strive in elemental advantage. Pink Bean seems to be the best balanced boss thus far, with only Paladins not getting a fair shot at things. But even Paladins are perfectly useful for a large portion of the fight, and beyond that, they're only a little behind Heroes.

ps Mage single target DPS on neutral isn't even as bad as you might think, not when compared to other classes unbuffed. No one is ever allowed to use their summons though, so they're only doing about 2/3 what they should be. But really, cutting elemental advantage leaves them with 2/3 of their best damage, and cutting their summon leaves them with 2/3 of THAT (assuming a boss would be weak to all elements, like, for fairness's sake, it should be). That's 4/9; that's less than half. Oh, and you say Mages are commonly disallowed from using their skill that has so far been called "broken and too strong", because of ignorant paranoia? That's great. Mages can touch 100k DPS EASY on their AoE ALONE just by hitting ~8 things at once (like uh i dunno zakum arms), and that's WITHOUT elemental advantage and without summons. Seriously, folks, Mages aren't as bad off as you think; they're discriminated against by ignorant players who won't give them a chance, and by the designers who have failed to give them a boss where they can be NECESSARY to a successful fight.