Aesthetic upgrades of visual effects are the only Special Edition changes I like. Some of the speeder shots on Hoth look bad and dated in Despecialized, so while I believe strongly in preserving the original, I also think there is value in modernizing the vfx so they look realistic and don’t take you out of the movie experience.
On the other hand, there are CGI upgrades in Star Wars and Empire that look like they were made in a different era and are out of place in the film. I cringe whenever I see the obvious computer graphics like when the Falcon is flying around Cloud City. It looks straight out of a video game cutscene and doesn’t belong in the movie.
The speeder bike chases on Endor still look great on Despecialized 2.5. I was very surprised, I thought they would have aged much more but they still look realistic to me.