About half the gamer population agrees with you. It is a reasonable position. But about half strongly disagrees and finds one day healing seriously disruptive to their experience of the game. Both sides sides have good arguments, neither side will convince the other. They are going to have to arrive at a workable solution. IMO HD and one day heals as default core is not a workable solution. I can houserule it out and play just fine. But I think they will lose a lot of people if they leave this stuff in the core.
But again, why? Isn't the point entirely moot, as I mentioned? I've been playing D&D since 1986 and I have NEVER, in any game with long natural healing times, had my character naturally heal. When I was young we just entirely ignored the rules and as I got older, we always had magical healing, either from a party member or from a local temple.
So what difference does it make whether you like HP and healing one way or another, especially to entirely reject the game over. Who actually uses that rule? Is it just the comfort of knowing its there? If that's so, WotC can go right ahead and set the healing at the "grittiest" (and I say that in quotes because I still reject how gritty it actually is, it's just a longer period of time) and I'll still happily ignore that rule and have my characters ready to go the next day. Thanks Mr. Cleric.