First I’ll preface with saying the 1997 SEs were the first I saw of the OT. I was given it as a gift on VHS for the holidays when I was a child. I’ve only seen the PT in theaters.

I liked most of them but anything that changed a character such as Greedo shooting first I hated. I do believe strongly in preservation of the originals though.

Since I like most of them I’ll outline ones I hated besides:
The new CGI song and dance number. I skip past it always on rewatches. Analyzing it from a non-comparison point of view even, it is complete filler and adds nothing to the plot and only pads the runtime. If featured at all it should’ve been featured as background during dialogue.
The whole stepping on Jabba’s tail. Totally unnecessary and wasn’t done well.

With all the edits they did I was surprised at how they didn’t seem to update the lightsaber effects in many scenes. I don’t know much about video production but I’d think that would’ve been one of the more easy things to revise.

And though this thread refers to the SEs and thus the 1997 revisions, I’ll add that the rocks added in front of R2 in a later revision was immersion breaking as it would be physically impossible for him to have squeezed in there unless he can turn into liquid or something.