On the contrary, I think that, especially in terms of lighting and the improved 3D model of the Enterprise, the effects did improve over time.
You're thinking about when they went to the lower rez model near the very beginning. Things like the engine tips improved, but the lighting got darker and the ship still moved really badly.
Everything is too dark. Highlights are midtones. There's some really odd camera moves, like when the E passes by and then the camera pans over to see the klingon pass by behind her. The Klingon ship looks like a video game render. There's a lot of strange shots of it off center, cutting off the top of the ship against the top of the screen. And, of course, there is the really unbelievable last second maneuver of the Klingon ship behind the E where it suddenly turns off abruptly and not even on its center of gravity.
It's as if they aren't even trying. And, unless the animators were first year trade school graduates, I doubt they would allow things to look this terrible without a bad director breathing down their necks and insisting it look this way.