The Riddler's car challenges were the worst part of Batman: Arkham Knight, and Gotham Knights must avoid it at all costs. While the Batmobile sections in Arkham Knight wasn't entirely without merit, the Riddler car challenges represent the worst parts of the game's implementation of the iconic vehicle. It's best that Gotham Knights just avoids the matter entirely.
Arkham Knight built itself completely almost around the Batmobile to address the sheer size and scope of Gotham City in its game. Arkham City managed fine with using the grappling hook and gliding, but Arkham Knight required something a bit faster to get around the map. The upcoming game will not have the Batmobile, opting instead for the smaller, more maneuverable Batcycle to get around Gotham Knights' version of Gotham City.
With this change, and other quality of life improvements made to the means of getting around the city, Gotham Knights appears to be taking everything that was great about Arkham Knight and polishing off what wasn't. The Riddler vehicle challenges should absolutely be considered in the latter of those two categories, as they simply were not engaging, and trying to improve them wouldn't be worth it. Best to just leave it behind in the Arkham series.
The Riddler Has Run His Course In Batman Games For A While
To take this sentiment a bit further, not only should the Riddler car challenges be shelved for Gotham Knights, the Riddler shouldn't show up at all. With villains like Mr. Freeze and Gotham Knights' Court Of Owls showing up, the game is already going to have quite a few plates spinning at once when it comes to villains. Having The Riddler there on top of it runs the risk of burning out what has already become something of a tired concept as far as Batman villains go in these games.
The Batmobile challenges were the last avenue left to explore with The Riddler in the Arkham games, and they were divisive at best. There has been no mention of The Riddler appearing in Gotham Knights at the time of writing, which is likely for the best, as the character has been played out in Batman games for the time being. Gotham Knights isn't in the Batman: Arkham universe, so there's no trouble with leaving the Riddler behind entirely.
It's good that Gotham Knights is taking and refining so much from Arkham Knight, since that game did have a ton of good gameplay ideas that were perhaps not executed as well as they could've been. But the Riddler challenges should be left at Rocksteady, either the car challenges, or the character entirely. Gotham Knights will survive without having the player look for Riddler trophies again.