Hola,
I just created https://bugzilla.wikimedia.org/show_bug.cgi?id=20768 ("Branch 1.16") and Brion was quick to respond that some issues with js2 and the new-upload stuff need to be ironed out; valid concerns, of course.
I proposed to make bug 20768 a tracking bug, so that it can be made visible what issues are to/could be considered blocking something we can make a 1.16 out of.
Let the dependency tagging begin. Users of MediaWiki trunk are encouraged to report each and every issue, so that what is known can also be resolved (eventually).
I'm calling on all volunteer coders to keep an eye on this issue and to help out fixing issues that are mentioned here.
Cheers!
Siebrand