No new libraries? I wonder if 2014's new Python implementation from Guido's employer Dropbox- Pyston, count as significant in your mind?
If you prefer to have no Google App Engine, Azure, Amazon or distro support other than Arch, then have at it. I'll keep that and PyPy, Pyston, Jython, IronPython, PyInstaller, not to mention all programs where Python is integrated like GIMP, all of this is Python2 only.
Potentially no new libraries (for new things and/or API connections)
Not sure how long new versions of existing libraries will keep 2.7 support.