Andrey, I'm truly sorry if you feel disappointed by my response but I'm afraid this is all I can say at this point.
I don't think we can be more transparent. We answer individual e-mail requests in detail typically within 24 hours including questions about our roadmap. In addition we've created this forum to discuss these things publicly.
The difference to Mendeley might be that you actually talk directly to people who make the decisions and can give clear answers. I could label this thread "Under review" and say "we are looking into it" and let users vote for 4 years even though I know it's not going to happen. It don't think that would help anyone.
I'm happy to discuss more why this particular feature is not on our roadmap. The short answer is that almost nobody asks for it while it would be very hard to implement. If we use our resources on such features we would be out of business soon.
We would love to make everyone happy but we can't. We give everyone a 30 day trial see if the product is right and we are quite proud to say that nobody asked for a refund yet.
Again, I understand you being disappointed about the lack of the feature. But I don't think there is reason to doubt my honesty here. Greg, Andreas and I have written thousands of support e-mails in the past 12 months and offline support just did not come up as something people are missing.
The sorting by votes feature was removed by discourse.org not by us: https://meta.discourse.org/t/does-anyone-actually-like-the-likes-column/18397. We hope to bring it back if technically possible at some point.