Isn't the judder partially caused by in essence duplicating frames in order to get the 30fps, whilst PAL just runs the film 4% faster at 25fps
Short answer: Yes.
Slightly longer answer: It's repeating fields (interlaced half-frames) that causes the judder when watching in NTSC/480i, rather than full frames - technically, NTSC is (was) 59.997 fields per second, rather than 30 frames per second. And since the shows were mastered in NTSC, they had to strip the repeated fields out rather than just run the film faster (early UK showings of TNG were "biked" over and converted directly, with all the downsides to both PAL and NTSC baked in, while later showings did the "DEFT" speed-up conversion. And some effects were filmed at 30fps and couldn't be DEFT-converted). But still, the gist of it is "yes"
