I get what you're saying; in GE64 there was a very unique "look and feel" to how the characters ran at a strafe, that was in part due to the original team's inexperience at designing an FPS, and in part to the limitations of the time - but combined made a product that was certainly unique to GoldenEye 007 and made it instantly identifiable.
I'm all for *some* elements of that being in GE:S, however, more fluid / realistic character movement is a compromise - and improvement - that gives the mod more credibility; with the updated textures, remade maps and guns, etc., trying to duplicate the original N64's movement would just make it look silly and out of place today, as nostalgic as it might be to do so. It's one of those things that were unique to the original but don't really translate to today - maybe a little of it could be worked in, but going too far would just bring down the mod's quality.