Can someone give me an in-depth explanation why Summoner is arguably the worst DPS?

[mvenom]

Giving Summoner PIE is denying them a secondary stat which ultimately denies them more damage. You would basically fix the MP issues but nerf their overall (weakest) damage. That solution won't do any good.

Or the piety could be similar to Healers having Accuracy on gear. Not like +20 pie per item, but like 5-10.

But this would give black mages more piety as well so idk how balanced that would be.