I've found the Fullerton reissue Jazz necks ultra slim and super fast, although it all started to change after the move to Corona.To begin with bodies were thicker, less contoured. Gone were the original vintage templates only to be replaced with generic versions.
Notably the Jazz Bass body shape changed and even started to become slightly smaller and less defined.
Yeah, this is exactly right. I bought my 83 Fullerton RI used in 87 (for $400
Anyway - fast forward to the early 90s and I had opportunity to buy a RI Jazz in Fiesta Red, an 88 (in other words Corona made, but again, had no knowledge of any of these details at the time). Wanting a bit more flash on stage I grabbed it ($600 at the time). I instantly knew it felt different, but never the less, I kept it. Worked bit by bit to set it up as close to my Fullerton as possible, but it was never quite there. It's funny, the neck really didn't feel any different to me, but the body was heavier, clunkier, not as refined. While owning this one I also picked up an an early 90s made RI in what I think was sea foam green, again - going for flash on stage. This one had the same issues as the fiesta one. A perfectly fine instrument, but in my hands it just never felt as good as my Fullerton. By the mid/late 90s my band had dissolved, I started a family, had no real use for either of these basses since I didn't really like them, so I sold both of them.
It wasn't until 2009 or so when I discovered the FDP forum that I learned what it was that made them different, and what made my 83 so special. Of course, looking back I wish I had kept them, as they were perfectly fine (just not special), and over the past ten years I have been gigging regularly again, would have been nice to have the custom colors for the stage, particularly since I had bought them for cheap. Oh well.