How can these tracks be fun? Most of the areas you mentioned come from games that are dead serious in tone and darkness, so how are you supposed to feel fun racing though there? Many of these areas are supposed to intimidate the player in their original games. Sorry but this is a straight contradiction. How can you laugh when driving past zombies, dead corpses, withering ruins and knife wielding Silent Hill nurses? You need to be a bit of a psychopath to enjoy this. And then the next question would be the items to use: what kind of items should that be?

How can these tracks be fun? Most of the areas you mentioned come from games that are dead serious in tone and darkness, so how are you supposed to feel fun racing though there? Many of these areas are supposed to intimidate the player in their original games. Sorry but this is a straight contradiction. How can you laugh when driving past zombies, dead corpses, withering ruins and knife wielding Silent Hill nurses? You need to be a bit of a psychopath to enjoy this. And then the next question would be the items to use: what kind of items should that be?

That would work much better.

I don't think you want to go down that route. The issue isn't just that the art direction for many franchises are realistic, it's that they don't mesh well together. With something like Smash, the franchises do blend well together. No character looks weird or unfaithful to the original style in the Smash art style. Cartoon Drake would look weird and would look unfaithful. Cartoon Bloodborne, too.

I think people take for granted how much of the design work was done in the original series before they made it over to smash. Bayonetta is a perfect example. She is already heavily stylized in her games, so not a lot of work needed to be done to make her fit in Smash.

It would be much weirder than that. Sonic is mostly sonic/sega characters, which blend better aesthetically. This is not the case with Sony.

If you're a good game designer, anything can be fun. Fun isn't just Muhsroom Kingdom. If Shadow Moses can be a Smash stage, it can be a kart racer track. And no, most of the areas I mentioned isn't serious in tone, "tracks inspired by" is the key, rather than full on hardcore representation.

House of the Dead stage in Sonic All Stars Racing

Are you scared shitless? To the point you won't have any fun?

I think the disturbing thing here is your definition of fun.

The original properties really dont. Panzer Dragoon has 0 in common with Shinobi which has 0 in common with Jet Set Radio which has 0 in common with House of the Dead which has 0 in common with Golden Axe or Outrun. It would be just as weird asking for a racer with those properties but Sega made it work, and if Sega can make it work, Sony can too.

If you're a good game designer, anything can be fun. Fun isn't just Muhsroom Kingdom. If Shadow Moses can be a Smash stage, it can be a kart racer track. And no, most of the areas I mentioned isn't serious in tone, "tracks inspired by" is the key, rather than full on hardcore representation.

House of the Dead stage in Sonic All Stars Racing

Are you scared shitless? To the point you won't have any fun?

I think the disturbing thing here is your definition of fun.

Why do you keep using SEGA All Star as some kind proof of concept? House of the dead is serious? Are you series? House of is all kinds of Japanese anime B class monster movie cheesy. That does for SEGA games especially in the 90's/early 00's  All SEGA  IP's are cartooney in nature lending them be meshed well with other. SONY IP"s dont have the blending power that SEGA,  Nintendo, CAPCOM, hell all Japanese companies do.

One unique feature about Japanese characters is that they well in both realistic and anime. Look at Kazuma Kiryu - He has realistic version and a Anime version that they use when dealing "meshing".