So Kevin, what's wrong with doing what I've already been forced to do with FCP Studio?…….
I simply have not upgraded the OSX on my Mac beyond 10.8.5. because that version of OSX still allows FCP Studio to run just fine, as it does with Aperture as well as a couple of other "passed by" Applications. The machine they run on is late 2009 / early 2010 and it's still functioning just fine.
If and when I feel I need to upgrade to Yosemite or whatever else comes down the road then perhaps it'll be time to buy a new Mac, but I'll always be sure to keep the older one if only just to run the Applications that have been cast aside or outdated by Apple or whoever else.
It's always made sense to me anyway if you're using a computer professionally, for editing or whatever, to have as little else on the machine other than the Applications you need for the tasks in hand and that's all, everything else junked.
Aperture, if it ain't broke, which it's not if it still runs on Yosemite or prior, then just keep using it and don't change up the OS,
As I said, that's worked for me with FCP Studio and there's no reason why it cannot do the same for Aperture too…...
Good luck anyway.