I have no intentions of buying a win 10 version. Over a year ago I spent more than I should have for a new computer (win 8.1) just to play JNPG ( trying to eliminate stutters and it didn't work ). Now I would probably have to spend over 200 bucks for a win 10 OS. With PG taking a firm stand on the new physics I don't see me spending much more to play this game the way it is. It's just not as much fun as it used to be for me.
It sounds like you've got more reasons for not wanting to buy the Windows 10 version of JNPG, than just the cost of the OS (which was free for me, during the free upgrade window that ran for months). I'd be surprised if the Windows 10 version doesn't deal with the stuttering issue (I take it you mean 3-click meter stuttering) better than the current version. I'm not a 3-clicker myself, but I did try it just to see what those who are were talking about. I did get stutter on occasion and can see where it would be a buzzkill.
The matter of the new physics is more subjective and I really don't know what we can resolve here about it. I prefer the new physics to the old, but I'd say they still need tweaking.