I think you are wrong. Hitpts have been an amorphous blob since 1e and the game has done fine. most dms either don't care or decide how it is and move on. Generally the more you specify and lock things down the more it hurts your game. When it's fuzzy DM decides and thing move on. Now what I really think is driving the whole 10 min rest thing is someone has convinced thier peers if make the rules more like world of warcraft it'll grow the base.If that's their decision, then so be it, but they should know that they're completely alienating any potential players who actually care about having a solid model for what's going on. That includes a good number of players from the AD&D era, who had figured this all out already.
"Amorphous" anything is the worst possible (lack of a) solution, from a modeling standpoint.