And you know MS doesn't encourage them how?
<rant>
I love how whenever someone doesn't like something about any game, it doesn't matter which one, it is automatically MS's fault, like they're some giant bogeyman who's sole intent is to ruin your gaming experience, and they're responsible for every last pixel that appears (or doesn't) on your screen.
First of all MS is a large corporation, with many many different divisions, the Xbox division is funded by the MS umbrella and that's pretty much it. people who work for MS outside of the Xbox division probably don't have any say what-so-ever about what happens in the Xbox division, and I would wager a guess that most of them don't even care. Having seen the campus myself I can tell you that the Xbox division is in it's own building separate from the rest of MS... "Xbox" might as well be it's own company using MS for venture capital.
Secondly, don't you think the Xbox team has better things to do like working on the official MS games, fixing bugs in the dashboard, getting the steering wheel and other accessories ready for launch, etc. etc. etc.
Most XBLM releases are delayed because the Xbox certifiers are overbooked with testing new content.
If Capcom wants to release an update for Dead Rising it's Capcom's decision, the Xbox team as it is has more content then they know what to do with never-mind dedicating people to complain to Capcom for you..
If you want more content write a letter to Capcom, blaming it on MS by complaining in a forum is like blaming your parents that the corner store isn't offering more flavors of Slim Jims... it's nonsensical.
</rant>