So what would you suggest for all the champs who do benefit from it? It's more than three by the way.
I realize there are some champions who would like Devourer but aren't super broken by it, but those champions are never going to get played unless the champions majorly broken with it are gutted, of which there are only a couple. And while Weedwick definitely deserves it, I'm not quite so sure anybody else deserves a gutting over this enchantment.
Most of the champions who are good with devourer but not broken with it need their own buffs. Shyvana for example, has been nerfed repeatedly over the course of many patches, and is now nearly useless, having both lower damage and lower survivability than ever before. Many other champions I can think of that would use devourer would do perfectly fine with either Warrior or Juggernaut.