I feel this is a game mechanic that's hard to balance properly. I think in a game like Fallout one of the core gameplay focuses is scavenging (some of my more memorable moments in the past games have been when I've been low on resources, sneaking through hostile territory and checking in every nook and cranny for useful items to get me through.) And you tend to lose incentive for all that scavenging when items aren't in short supply, and the tools you have with you are always reliable.
At the same time, I dislike when a mechanic becomes tedious - that's a sign of flawed game design in my mind. (ie, if the purpose of a videogame is primarily to have fun, then any time you are not having fun or doing something you find boring, then that speaks of room for improvement.)
I think the proper balance is items degrading enough for an eye towards inventory management and careful scavenging to be useful, yet not to the degree that it takes away from other aspects of the game. I would hope that Bethesda find that sweet spot and then justify it with in-game logic rather than figure out what was a "realistic" degree of degradation and then build the mechanic around that. In my mind gameplay trumps realism any day (especially in a game like this.)
Ideally, I would like item maintenance to be mostly a down-time activity that you tend to between dungeon crawls, back at home base, rather than something you're going to be finding yourself doing multiple times in an outing. Finding a weapon while looting and using that to improve the DUR on your weapon is one thing - but having to bring up the inventory screen after every battle just to make sure your gun doesn't become useless would be going too far, I think.
I believe the idea is to make for interesting gameplay moments - so that sometimes you find yourself in a tight spot with nothing but an unreliable gun that keeps jamming, for example. To me, a lot of these mechanics are more important in terms of supporting those kinds of interesting and memorable gameplay events than being realistic.
(For example, I played New Vegas on hardcoe primarily, but found it rarely offered me anything interesting - water and food were plentiful that I never was in danger of getting too low in either of those, and the resting mechanic just made it so I arbitrarily had to sleep on occasion - which broke up my gameplay rhythm in a way that just offering some advantages to resting didn't. I didn't want a Hunger Meter just so I'd have another bar to manage, but so that it could support the gameplay aspect of playing a desperate Wasteland survivor scavenging for every useful bit - to be honest, I think giving healing properties to food and making Stimpaks much more scarce would have led to the same gameplay perogatives. And likewise with resting it would often crop up at annoying times - I much preferred breaking up my gameplay rhythm when it made sense to me. I would still use beds whenever it made sense to me, and just giving me a small XP bonus was enough incentive for me to make use of that on occasion. ie, I probably rested just as often in Fallout 3 without hardcoe mode as I did in New Vegas with it.)