The fact that all of your screenshots are of the same area, combined with Kiylo's image from above, is...
Telling.
My suggestion would be to focus on all parts of the map equally, lest you create a jarring contrast between the detailed areas and the rest of the map that actively disturbs the player. It's kind of like putting Red and Cyan next to each other. Sure, both are pretty intense and kind of grating already, but putting them together definitely does nothing but exacerbate the issue. Salt in a wound? Bullet in a paper-cut. ... actually, maybe the first but definitely not the second.
The theming the City(?) Area is also confusing, what with the megablock and city aesthetics conflicting so harshly. I'd definitely either make textures that explicitly combine the two, or alternatively just pick one over the other.
More track based than visuals, the race seems to be composed of mostly right angles. Right angles are fine, but then when every turn is the exact same thing, it quickly becomes boring. Variety's your friend, and the curve tool is theirs.
TL;DR, this map could definitely benefit more visual consistency and more physical variety. And for the sake of all that is holy, please cut down on the GFZWALL. I'm almost begging you. Not quite, but it's pretty close. Which means you should almost definitely listen!
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The (Visual and Physical) design is sort of bland... <<<I'd suggest for you to try out custom textures. Although, the ones provided by kart can still do well if utilized correctly. Plus, the main (gray) road could be spiced up a little bit. Maybe try coating the sides of it with sidewalks?>>>
