And long before this gacha change, Sanahtlig's encyclopedia says there will be an auto-sell function (around Phoenix's reprint in september). This should also make getting R weapons less annoying, if it works the sensible way and sells all the N weapons while you are pulling.
i actually use those N weapons and eidolons as exp fodder since... it actually does rack up...
would help when there's nothing to level though
needing R weapons and such seems to be eternal with this game... after all, there's bound to be something better than what you got released down the line