I think this article is on the right track, but I agree with you that you shouldn't necessarily minimize the number of features you have. I think, like the article said, your app should be known for doing one thing really really well (i.e. Google = search) but it could also have a lot of other features. These features should augment the one major feature that the app is known for and they should be simple to learn so you don't overwhelm your users.