Definitely yes. Them or others, whatever. And Not for every issues. But I want to ear about issues that have been worrying for a long time and/or annoyed a lot of people, or that are very complex and shady. And the only way to encourage communication about bugs is to congratulate people for their fixes/problem isolation.
Yes. As an industry, we're not very good at recognizing the great things people do. We tend to focus solely on mistakes. It's not easy to admit failure, and if we want it to continue we should recognize the effort it takes.