I had the exact opposite experience with UserVoice pages, at least the one for Accessibility. Someone requested that MS integrate my startup's reading technology into MS Word/Outlook/etc on the Accessibility UserVoice. This suggestion gained steam and was the top-rated suggestion for years. MS never engaged with the suggestion, and when I later asked an accessibility person why this was, they told me that the UserVoice is staffed by outside contractors, and that it's not one of the more important places they look for feedback. This was consistent with what I saw, which was that they didn't engage with the most popular suggestions on the Accessibility UserVoice — they just ignored them.

I think it's pretty lousy that they set up a page to solicit feedback (especially accessibility feedback) and don't pay attention to it. It causes people to waste time describing issues, asking for help, and voting on other suggestions. A year or two ago they got rid of the UserVoice page, and they now tell people to use Twitter to make suggestions.