Because it needs dev-python/hacking-0.8.1 that needs <dev-python/pyflakes-0.7.4. And that last one cannot use python 3.4 as I read in its ebuild
In openstack, generally this kind of block is cured by a bump which won't be limited by <dev-python/pyflakes-0.7.4 and this 'offending' ebuild can be safely purged. python-heatclient is a relatively recent addition. Best get an update from Matthew
Removal of python 3.x is fine for this package. I think some of the openstack packages had it added prematurly. I'm hoping they will have the needed dep changes by liberty.
Well, since upstream says it doesn't support it, that's fine.
fixed, tested changes through tox for py34