GSHamster said:
But we're a self-selecting group. None of the newbies who 'encountered a rust monster, got their equipment toasted by it, got TPK'd in the next room, and gave up because this game was stupid' bother to post on Enworld. They just silently stopped playing.
We are not the only people that WotC makes D&D for. Interpreting everything through the lens of our own personal experience is not good enough.
a) I have yet to see a player stop playing silently instead of stopping with a loud display of disgust and a tirade of why he thinks the game was dumb and silly.
b) If I have to take a representative statistical sample every time before I post something on ENWorld, I guess I won't get more posts in for the next 2 years or so. Everybody here is posting from or interpreting through the lens of his/her own experience, and I doubt that is going to change soon (or at all

).
c) The same newbie would have stopped playing when his character gets killed and eaten by a carrion crawler (6-8 saves vs. paralyzation anybody?), dismembered by the ogre, or bloodsucked dry by a swarm of stirges. Some people think Monopoly bland or silly, too, and stop playing because they habitually land in jail. Still no reason to change it from "Go directly to jail, don't cross Start, don't get any cash" to "Go to jail, collect any cash you are due while crossing the playing field, and if you roll a 1 on 1d6, you're scott free".
Whizybang, I agree with your suggestion of a few variant rust monsters...or simply new monsters with a comparable ability. If this suggestion had been a new monster, I wouldn't have given it a second thought, it was more about the direction some design decisions went in remaking it that drew my attention.
Mr Mearls, this was not meant as a criticism that you were trying to "dumb down D&D for young newbies", just so I'm not misunderstood. I actually welcome any attempt to simplify D&D as it is for new starting players of younger ages. But even then it's easier to go with "monster hits, rusts your sword and starts eating it" than "monster hits, puts your sword under a magical curse that weakens it with time until it can eat it, if you don't get it out of reach in time". Less bookkeeping and a more immediate effect create a more memorable impression of the threat a monster represents, in my opinion.