Simulation enthusiasm

I sometimes take a trip to the game developpement world through Gamasutra web site.
Which is, by the way, an excellent site. (you should create an account...)
I've read 2 articles.
The first one The Perils of Bottom-up Game Design:

If you're a software engineer, your natural temptation is to figure out how to program it(simulation) and see how it works. What are the core mechanics of the simulation?
(...)
Bottom-up game design is based on an assumption that any process that is subtle or interesting to program is also going to be interesting to play with. That doesn't necessarily follow. For years I was intrigued by the challenge of programming a traffic simulation. (...) I had gotten all excited about the software engineering problems and ignored the fact that it needed to be enjoyable.
(...)
the temptation to "improve" your software with one more feature, and then one more still, just because you can. In consumer software, the result is usually a bloated, awkward mess like Microsoft Office.

I feel guilty about those unnecessary features. Today I try to stick to those 2 rules:

• Don't had features the user didn't ask fo even if you find them "cool".
• Don't create a "'big realistic system" if it can be done simply (but not realistic who cares if the user is happy with it!).
  

The second article: A Software Process for Online Game Tools Development is discribing an XP development process without knowing it, it seems game development and entreprise development are in two parallele univers that don't communicate... too bad!