If the section were renamed to "In Development", instead of just "Upcoming", then a developer might be more prepared to head back to the thread, post-release, in order to discuss upcoming changes/enhancements/updates/more, without constantly bumping the actual game's thread.

Personally, I don't like when I bump a topic myself, unless it's a Development-based thread. Then I'm happy, because most of the posts of those are going to be by me.
A game thread should be clean of dev-stuff, and more about the end-result.

The way you currently have it, once a game's locked, the "Development" thread gets locked, and then everything ends up being splodged into the single thread.