Rdm isn't completely irrelevant, in conjunction with Geo, it has a higher Macc and some useful buffs and debuffs that only Rdm gets, Frazzle 3/Distract 3, JA to force land enfeebles, and on a few gimmicky fights debuffs such as silence or blind are relevant.

That said, I'll agree with you that Rdm is pretty far back in the support lineup. Bard is debatably further back though, which is a odd, considering Brd and Rdm were on top of the world for a long time. I'd also argue Bard needs a buff more than Rdm, or possibly buffing melee in general might make them both make a comeback due to synergy.

Allowing Temper/Temper2 to be ally-cast would go a long way to improving their synergy with a melee party, and yes, some sort of magic evasion buff that stacks would also be nice, though, people don't use Addle 2 nearly often enough, it has a macc penalty which is for the most part, the same thing.

A lot of the current meta has arose from melee groups not being viable due to ridiculous enemy TP moves, along with skillchains+magic burst being strong, fixing the insane danger to melees might change the landscape a lot.