Sounds good actually, I really do like to do a bit of roleplaying in RDR and having to eat, etc. would be pretty interesting, as long as it wasn't obtrusive. The player should never have to stop mid-fight to grab a drink.
I don't agree though about not needing to break the law being boring. I for one found it quite refreshing that I could play as a good guy, (albeit a horrifically murderous one) and still enjoy myself, after all I've played the bad guy plenty times in other games, usually out of sheer boredom. In RDR I can actually play at being an elusive lawbringer, riding out to bring in bounties and defending the town from the occasional randomly generated criminal. Plus the police where just enough of a problem with the bounty system and all that I rarely went on a crime spree without carefully considering the consequences of my actions. Except for when it came to card players, cheating bastards, blackjack in particular can be unreal at times, which makes it all the more satisfying when you up and blow the smug smirk off of the card dealer's face, regardless of the consequences.
Where was I? Right, right, the food and drink thing. I think it could work, maybe it could be tied to the fame stat, if you were well known enough then people might give you free food, drinks, rooms, etc. out of either fear or respect, depending on your honour.
Also, the respawning horse thing. The first time my horse died out in the wilderness I felt a mixture of exhilaration and fear. There I was, far from civilization, vulnerable to predators and bandits alike. Would I dare try to hoof it back to the nearest town? Would I lay in wait, killing the next traveler I saw and stealing him horse, even if it would stain my own self imposed good guy image? Would I try to lasso and break in a new horse using nothing but a lasso, my wits, and the element of surprise? Then I absentmindedly whistled and my magical, reincarnating horse trotted up, thus ruining the drama of the situation and causing me to drearily ride back into town to be cheated by a slick card player who I would promptly kill.
Also, while I don't agree with the idea of non-regenerating health and Dead-Eye, I like the idea of health that would regenerate to a degree but still require medical supplements to get back to full. But a gunslinger shouldn't have non-regenerating Dead-Eye, sure unlimited Dead-Eye would make the game too easy, but it manages to regenerate at the perfect speed for me. Plus, it wouldn't make much sense if a hardened badass had to stop a take a swig of a magic potion every time he used Dead-Eye.
Wow, long post.