I've had this exact same experience before - you build a neat core product that gets a decent core following, but then your team isn't sure where to go next. The first thing that always happens is that everyone has ideas for new features to bolt on that they've seen elsewhere.
The discussion quickly moves from 'How do we make this better?' to 'How do we implement this feature?'. Engineering logic kicks in - this is a great challenge! We need to show how well our design works - during the design phase, we kept in X and Y which we can now leverage to complete this new feature!
Once you've moved from thinking out what the customer wants to use to 'how do I make this thing work? should I cut a corner?', then you have already lost the customer's attention.
The article has a great take away and I agree with it completely. Don't add features until you understand how and why the customer is going to use those features, and most importantly, if the customer will pay (or increase retention) for that feature.