There are many factors that can affect a release schedule. We don't maintain a list of "what's coming" because we don't want to make promises that we later find out we can't keep. If there's a particular request you're interested in, let us know.
There are many requests like rich text case events, case event edit, notify, and custom fields that spent years on the wish list prior to their implementation, so two years does not mean it'll never happen.
Sometimes new engineers join the team, look at something that has been languishing and have a new insight that leads to fast implementation. Bulk reply was one of these. Sometimes, an internal person (me) pushes to get a particular feature on the schedule. Notify was one of these (and I'm proud of it).
Customer feedback is the single biggest factor that makes things happen, so keep communicating with us about your specific needs!