I think this is an issue that rears its head because of tabletop gaming vs. crpgs trying to be like them yet designers not wanting people to be able to rest everywhere because it is unrealistic and or too easy. in PnP you had a chance of random encounter when you rested, Im fine with having a chance (even in a city - thieves, brigands, ladies of the night, etc.) of a random encounter.
I guess the other question is: Will it add to gameplay and realism or immersion? Will the design implimented for restign add to the tactical decision making for the game? If so, then its probably worth adding. Also, anything to stay away from a constant grind/kill fest that we see so commonly in modern games. Lets be realistic, even heroes need to lick their wounds. Also, knowing your hero is mortal etc. adds to your accomplishments when you do succeed imho.