I stuck with Snowy for as long as I could, because I'm pretty much in agreement with your assessment of the more recent versions of OS X/macOS, but I broke down and upgraded
  1. primarily because Safari was getting to be a nuisance, and I totally dislike Firefox, and
  2. because I was simply falling too far behind - I went from Snowy to Yosemite, a jump of 4 versions. - and caught up with it before it caught up with me.
If you're covered by AppleCare, you might try calling and seeing if they'll accommodate you with an earlier OS than High Sierra, but alternatively, you can take a look on Ebay, where a market for non-current OS's has proliferated as a result of Apple's failure to make them available.

When I was in your position I archived the installers for the versions of OS X/macOS that followed Snowy until I no longer needed them, and l very strongly suggest that everyone who's passing on upgrades do the same...just in case.

The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire