The speeders are transparent intentionally to overcome the common problem of black lines surrounding matte work. They should have been able to re-matte it digitally. This was probably hidden by the film-to-film copy and brought out in film-to-video. It doesn't make it less worthy of fixing.

Especially after they did fix so many things. I saw the original versions on VHS a few years ago, and it was amazing how the effects, which everyone remembers as seamless, were so ropey when watched with more modern expectations. (For instance, the bit where someone's about to get thrown into the sandworm thing in the desert, but then gets rescued -- all the ships and particularly their shadows just look completely amateurish now on the original, but fine on the remake.)

Peter