This topic would have made more sense in SRB2 discussion or something.
Anyway, I doubt that's a good idea. Remember the porting rule from Level Design 101: make sure the ported level translates well into SRB2. And I think it would turn out terrible because the gameplay of Mario Kart are so different from SRB2. The tracks themselves always had to be pretty empty, because gameplay in Mario Kart is even faster than in SRB2. Also, the scenery really defines the track in Mario Kart, and SRB2's capabilities are too limited to really nail the scenery on any Mario Kart track except those of Super Mario Kart, which would be lame for the reason you already stated.
More than that, though, the gimmicks in Mario Kart tracks that provided challenges to keep everything interesting would be almost impossible to include in an SRB2 level. I could sort of envision a SOC'd Chain Chomp, but I don't think it would ever be as good as the real thing, and enemies in a Circuit level are a bad idea anyway. I actually think that the Kalimari Desert train would be possible with some really complex PolyObject work, but it would be extremely glitchy. You might as well forget Rainbow Road from any game but Super Mario Kart, because those tracks sloped and twisted in ways that SRB2 couldn't handle (even if you used fake staircase slopes, it would look quite ugly).
The problem is that the best levels in Mario Kart are as good as they are because they take full advantage of Mario Kart gameplay and physics. SRB2 is a totally different game, and there would be a lot of elements in Mario Kart tracks that would not be fun, severely limited, or just impossible. SRB2Riders had an unlockable Mario Kart mode, and it never worked that well, despite the fact that CZ64 custom-programmed the hell out of that mod. If you ask me, Mario Kart should be Mario Kart, and SRB2 should be SRB2, and it's best if we keep it that way.