What are the main reasons you want an API?
Worthwhile communities need to be maintained by barriers. The kind of barrier that I personally enjoy most is, "Crappy enough interface that only people who really like the content will be motivated to show up."
I grant the existence of useful content there and a good API. However after one too many brushes with how differently moderators think about stuff than the people who I liked talking to did, I have demonstrated the truth of my comment by choosing to leave.
StackOverflow works for a lot of people. But for me, personally, a stripped down interface and less moderation is a better experience.
Presentation, along with content, is a better experience than just having good content.
You having the interface you want shouldn't impact my having the interface I want.
An API allows everyone to have the interface they want.