It's an ongoing thing around here about how our vendors need to test their products more and take input from the librarians and end users. An update JSTOR made very recently is an example of how they need to ask a diverse set of users.
My biases: I come from a research institution with a large collections budget and I feel very strongly that users should start with research databases that are indexed and topical for subject based searches, not start with digital libraries. Digital libraries house the full text - now once you're there if you get recommendations or what not, fine.
So JSTOR - and they are very, very quickly fixing this - made it so a search done on their site would bring back results not necessarily available or accessible to the user. In other words, it doesn't default to show only subscribed items. Now, if this were a research database, it would pop up an open url resolver link so you could look for an owned/licensed copy. JSTOR didn't offer that either, so users at smaller institutions (or ones that don't license all of the collections) learned of interesting articles, but then were offered an opportunity to purchase them with a credit card, not assistance in finding a copy their library had already purchased. Meredith Farkas describes this.
If they had asked me? Neither of these things would have come up. First, we own most things that come back in the search (particularly in STEM fields). Second, I wouldn't search on JSTOR anyway, I search in Inspec, Compendex, Web of Science, Aerospace & High Tech, MathSciNet, etc., and then I link out using our open URL resolver to get to JSTOR. From time to time for my own interests, I'll browse the TOC there, but that's maybe once every few months.
So it's not just getting a librarian to give you feedback, it's getting a diverse group of librarians to give you feedback.
Oh, and the problems Wiley caused themselves? Well... apparently they didn't remember when they fixed this exact issue before. So you have to listen, respond appropriately, and then remember not to un-do!