>>48367947This. They already fit the setting for mutlple reasons. Also the Decidueye family is too new to get a regional evolution. Plus, Dedueye communicates its Archer concept so blatantly that a new evolution wouldn't be able to make it fit any better.
If Game Freak wants to fix them, the most logical solution would be to giving them Battle-Bond forms or something similar (possibly they would gain the ability to become "Nobles" with boosted stats and slightly altered appearances.