Well put, whether people like it or not, we're going to have some level of downtime, and that downtime has to be filled with something, and DPS is going to be the only viable answer for that with this games design.

Of course, we could explore other avenues, like crowd control, buffs, debuffs, etc., but damage is something that's always going to be needed. Not every boss is going to have stunnable adds, or interruptible attacks, and once everyone has their buffs up, we still need something else to do. Even Astro will have to rely on Malefic when all other responsibilities are finished.