I don't mind Mario Kart World gameplay-wise for the most part, I think the routes are a nice addition and my only gripe with them is that they are essentially guaranteed in worldwides and Grand Prix has been entirely gutted to make them take up 90% of each track outside the first one. If we got a traditional Grand Prix (3 laps on all 4 tracks) and could play normal worldwides with only lap-type courses if we choose, I'd have no gripes with them existing at all. Ironically I'm much more bothered by the fandom's normalization of a mistaken name for them, as intermissions are the waiting lobbies between races, not the route tracks.
Other than that all my gripes with MKW gameplay/function-wise are massive nitpicks. Why do the CPUs in free roam try so hard to lose me when i just want to take photos with them for example. Why is it impossible to take photos with two players offline. Photo mode in general is disabled in way too many instances where I'd want to use it. Its filters are also extremely underwhelming compared to Odyssey's, which afaik completely returned in DK Bananza so idk why Kart decided to make the selection significantly lighter.
By far my biggest gripe with World has no bearing on the gameplay itself & is the same one i've had with every Mario Kart before it and likely will continue to have based on Nintendo's refusal to acknowledge this gripe even as a hypothetical. It is far too limited in what from the Marioverse is being pulled from. I've felt this hurt for over a decade as someone who's very much rooted in the Mario RPG corner of the fandom. I just wish my corner wasn't considered too small/insignificant to throw even one bone to. And every other corner of the fandom who has experienced similar disregard should have at least one character as well, at least for subseries that are still actively running. Obviously there has to be some limit, but I think the current one is way too tight and opening it up to all currently running Mario-adjacent subseries, with maybe one or two bones for dormant subseries that have a notable cult following (like Wario Land), should be reasonable.
Yes there will be infighting about certain characters getting in over others, but that's always been the case even now (Kamek & the Koopalings being cut has already been taken out on the NPC drivers for example), and is just a reality of any fandom that shouldn't be taken as a reason to just not bother touching certain parts of it.