There seems to be a consensus that we cannot fully release tycho without fully releasing tycho-extras and vice-versa; that we can release fully test tycho without fully releasing tycho-extras and vice-versa...
So let's list of the pros and cons of the split. As I'm biased, I'll just list some cons
* 2 times more steps in the release process
* Gerrit tests miss some failures caused by current change on other repo
* Harder navigation for contributors (am I in tycho or tycho-extras, where is that other one...?)
* Some key features of modern Tycho usage (pomless, reproducible qualifiers with git) are in extras
* Some inconsistencies: source-bundle in core, source-feature in extras
Unless the pros growth manage to weigh, I think you know what's going to happen: we'll try merging tycho-extras into main tycho.