This absolutely works, if you've developed an app you should definitely have a support/feedback form somewhere.

Just launched our second app and we decided to include this, and I think it's had a hugely positive impact on our ratings and reviews. Where people would have left a bad review before, now they're submitting feedback straight to us. It's also helped us prioritize some things after getting the same question repeatedly.

It's a little more work (we've been following up on all feedback), but it seems to go a long way.