And exactly why covenant-lock specificially is a good thing? You know what is also cool and traditional in RPGs? Permadeath! Let's add it too. Is it a good idea? If not, then "cool, traditional, RPG" is not a enough to justify anything. If yes, then I have a whole bunch of other suggestions that should be implemented.
RPG is already extremely vague concept. DnD, Ultima, Witcher, Final Fantasy, Mass Effect, Diablo, Space Rangers and WoW are all RPGs.
Ah, that Warcraft 3 where you have to chose a faction once for the next two years of your ladder play and can not change it? Or was it that you had to chose a single upgrade path and lock it in for the next two years?
Oh, I remember! In WC3 you could freely chose to play whatever race with whatever build- and upgrade-order you chose every match with zero consequences on another one. And it wasn't tied in any way, shape or form to your single-player campaign.