Simple solution... Announce Wine Release 2004mmdd will be the last "stable" release and future downloads are at your own risk until further notice then go ahead and break it. It saves parallel trees and/or branch maintenance and allows developers to have their way. I would speculate that Wine would probably not be broken all that long anyway (maybe periodically) but would permit you developers the latitude required to very likely accelerate the 0.9, 1.0 goal time tables.
I am not a developer, I am a user and have been learning C and how Wine works in my own spare time for the past 3 - 4 months and starting to understand some of this. I do have a formal education with extensive experience in scientific/engineering experimentation techniques, quality assurance analysis, etc and direct customer relations as a result products manufactured and do know that progress, especially when expedited, requires good communication and sometimes breaking things when required (it's not released for production yet) to achieve the goal.
I realize this is a philosophical discussion as of now and since I am not at developer caliber - yet, you will all probably take this writing with a grain of salt but my grain goes to the break it side of the scale with appropriate notification(s) and get this project to beta asap. If there is concern regarding user flack, run a test announcement, then reasses.
Roger