I like the idea of failed Death saves indicating a wound this is sort of an extension on that.
There are a reasonable number of attacks that do ongoing damage (though many use fire -- which for classic regeneration is a stopper)
I am trying to design a sub-race with "true regeneration" ... one way was to give nice bonus's so that those bleeding injuries didn't last or even start and I was thinking auto stabilizing heal check even if unconcious....
and it conceptually works, but without some real long lasting wounds the ability is perhaps less interesting.
Dragon Masters (with Art)
The
RAW current regeneration ... is more, invigoration (providing energy) and inspiration (morale)... which are quite nice things for poets, preists and politicians to do (bards, clerics and warlords).
but not quite regeneration to me! ... I wish you could hear the song in my head.