Very interesting thread. I bought a StudioCat Laptop Pro running Win 7 Enterprise in early 2015, and it works just about perfectly with Sonar X3 producer: fast, reliable, plenty of capacity for plugins, tracks, etc. So I wonder not only about the OS upgrade; I wonder about upgrading Sonar too.
If the tools you use are effective and efficient, not to mention inspiring, what's the marginal gain from changing those tools? To put it another way, is your OS the most important thing standing between you and more/better music? Are the functions and features in your current applications constraining your output?
For me, the answer right now is no. My tools work brilliantly. Pursuing different tools right now will have less of an effect on the quality and quantity of my output than writing better music and spending more time producing it. The tools have evolved to the point where the delta between what I have and the state of the art is apparently marginal.
Something will come along sooner or later that's impossible to resist, either because it's obviously much better than my previous status quo, or the manufacturer leaves the user no option but to upgrade. Until then, I have a stable, fast machine and applications that have already dramatically exceeded my expectations, and I can spend my time making better music, as opposed to messing with the system that I use to make music.