Just as a counterpoint (not an attack on your sentiment), I thought the blue paint and especially the neon ball players were a much needed face lift in the late 1980s. To my eye those squares look quite dated. For example when I saw "The Wiz" for the first time (on TV), it had a segment where they end up riding a motorcycle through a mid-1970s Shea Stadium with the colored squares, and my first reaction was "my God, that's hideous". From a distance, the squares mostly recalled the exterior view of the artwork that elementary school kids stick up on their classroom windows, and otherwise it was a plain concrete bowl with visible ramps.

It's worth noting that I was born in 1970 so the 1950s-1960s minimalist/modernist look in architecture is something I have never felt in tune with. I like some of the more futuristic examples of the era, like the Unisphere, or DisneyWorld's "Tomorrowland" icon, but adding the somewhat garish blue and the electric neon line figures at least made the ballpark stand out and project a more brash attitude. I would have preferred a look like Baltimore's Memorial Stadium or Dodger Stadium to the "original Shea".

I suspect a lot of the nostalgia for that original look of Shea comes (and rightly so) for those who were able to be there in that time (which I was not), and associate that look with the Miracle Mets. Nevertheless my opinion is not based on nostalgia for the 1986 Mets, either; I actually was not a Mets fan (or a baseball fan at all) at that time.