I don't know about other Archers, but we have a decent MP pool and most max-level equipment offers a little MP+ if you're willing to wear some of it. I spend as much time shooting as I do using utility spells like healing, Siphon TP, even Sleep if needed. It has the capacity to be a supporter. Lancer is also in the same boat, having decent MP for being a melee. If you're super-hardcore, you can even push into high PIE tiers to use a (albeit gimped by not being a main-class affinity) DOT if nobody else is on deck.

And I don't know where people are getting the idea that Bloodletter is affected by PIE in any way. I do have a (baseless) theory that Foeseeker might have a PIE mod though. "Have faith in thy aim" and whatnot.