The early TNG uniforms looked good, but only when the bodies inside them looked good.
Yes, I'd agree. I think they're the best uniforms (very futuristic, a real design statement, and in keeping with the idea that fabric tech is subtly different to now) but just would have looked awful by the later seasons, given how figures were changing.
It's very subtle. There are two seams running parallel down the front of the jackets in season 3 that get lost in later seasons.
The first iteration of the mandarin-collered duds with the seams and streamlined hem were featured in the first five episodes of season three.
The front darts in the first iteration were really useful in terms of shaping the uniforms to get a better fit. Shame they got rid of them. The later iterations were probably cheaper to produce, and more easily altered to fit different guest stars. But the core cast could have kept the better-fitting darted versions.