In a tasting at the producer in 2016, I preferred the 2015 straight Santorini too - in fact it was my favourite dry white of the trip. Even that one is not cheap over here, but worth it IMO. I think 2015 was only their 2nd vintage, and they didn’t do a single vineyard one back then. The 2014 was not as good, and they said they made some changes (can’t remember what) for 2015.
I certainly like the cheaper Thymiopoulos wines, but I am not so sure about the others. And I really mean “not sure” rather than suspicious - they are not meant to be drunk young, and I have no experience of drinking fully mature Naoussa. The closest I have got is an 8yo Rapsani, which went down very nicely.
In fact I suspect very few have the ability to judge how different young Naoussa wines will develop. Even with Claret I think it is a difficult trick to pull off, and there are considerably more people with experience of Claret over a decade or more, and more wines to get experience with.