i agree. forcing a repository switch before the split seems hasty. better get stable 7.8 out the door with the current system and work out the repo switch in the 7.9 timeframe.
If it didn't "work out" during the 7.7 timeframe, what makes you think that it will during the 7.9 timeframe? And what's "hasty" about a repository switch that's been in the works since 2006?