Speaking as a user, I seem to recall having multiple versions of python installed in the past, and never really knowing or caring which version was being used so long as stuff worked. If you want to install python-3.14159 in the stable tree, than go right ahead, so long as anything that doesn't work with python-3 can still access python-2 and does so without me knowing, it doesn't matter.

So the question isn't SHOULD python-3 be stabilised, it's what will break if it is surely?