PS: I still own the same PS1, tho the reader might not working 100%.
Were it not so buggy, I think C&C generals ranks pretty high on fun modern RTSes.
I think it's a case of being better when it came out than another thing was when it came out, despite the other thing being comparatively better without the context of its time.
III has a better and more interesting story telling. But gameplay wise I really like the starcraft 1 system without the heros. I think warcraft 3 adds too much complexity and gimmickry that takes away from fun RTS gameplay.
That said, Warcraft 3 mods were the shit. There were so many fun and inventive modes of play that you could just barely do with starcraft and not at all with warcraft.