I think in the case of TNG you would keep the shots as close as possible to what they were, save for instances where it's possible to significantly improve the visual flow of a sequence (say you have your ST signature Enterprise fly-by sequence composed to two reverse shots, and you realize you would get better fluidity choosing a different angle B-shot; that sort of thing).
Ideally, they might even have photographic visual effect elements saved that they could simply re-composite for HD. I'm not clear on exactly at what phase in contemporary ST's production that material was shifted from film to video (it was well before final editing though, which is what makes a TNG remastering project tricky).
The ultimate goal though is to bring TNG up to the resolution of HD. There's nothing 'wrong' with most of the effects as they are, whether they have photographic elements they can reassemble or need to mimic them using full CGI instead. It's not like TOS where many of the effects really were in terrible shape due to the photographic techniques of the time.