For me it's not the castling stuff that's the issue in 960, it's the fact that both sides have to mirror each other. I feel like that defeats the thrill of having a totally random position. People claim that there would be unfair immediate tactics one side could play on the other in non-mirrored positions, but I haven't seen any examples of this. All pieces are still blocked in by pawns, and any tactics on pieces could be blocked by such pawns after moving. I have yet to see a "winning" 960 position on move 0 due to lack of mirroring.
Chess18 -- better than Chess960?
For me it's not the castling stuff that's the issue in 960, it's the fact that both sides have to mirror each other. I feel like that defeats the thrill of having a totally random position. People claim that there would be unfair immediate tactics one side could play on the other in non-mirrored positions, but I haven't seen any examples of this. All pieces are still blocked in by pawns, and any tactics on pieces could be blocked by such pawns after moving. I have yet to see a "winning" 960 position on move 0 due to lack of mirroring.
https://lichess.org/study/DZgXKpnd
This is a double chess 18 (chess324) and double fischer random position that gives white a ~+2 advantage from move 0.

I had written about Chess 18 in a Letter to the Editor in the July 2013 edition of “Chess Life” magazine. I hosted a "World Championship" prior to the Timber Moose Event in which Mike Commisso was crowned Chess 18 World Champion, so I would contend that GM Naroditsky needs to play a match with Mike Commisso :-)
Shouldn't there be greater opportunities in the long term that Chess18 perhaps catches on as it is intermediate between Classic and 960.
Maybe more people who are not 960 fans are more willing to play C18. For instance castling is normal and no issue.