There should be three or four tracks primarily dedicated for the ZONE
mode, at least. The ZONE mode has a lot of potential on its very own that
isn't fully explored yet. If SL does it right, then the ZONE mode can become
something very unique in the future.

Despite the standard tracks are quite good, most of them aren't built for
high speeds. But don't get me wrong here, I don't want to see tracks that
are mainly straights. Quite the contrary is the case. But building good
tracks for ZONE requires some good knowledge about curvature such that
those tracks / curves become a pure joy to race at different speeds. And I
also want to see well placed ramps, tunnels, and whatsoever.

Imagine a track with different stages (routes) were each stage has its own
difficulty (depending on speed) and were each stage is geometrically
connected with another stage that only becomes "accessible" at a give
speed or by taking a certain risk.