In my opinion, the problem with <$> is actually a problem with Haskell, which is that there's too damn many "operators" -- it's hard to keep track of them all. This also makes them hard to search for. When I search for "kotlin question mark colon", the first page of results is flooded with results about the Elvis operator (also a very memorable name for future searches, if I forgot). Searching for "haskell dollar sign in angle brackets" unearths nothing.

Something as common as option types (which is basically how nullable types are used in Kotlin) deserves special syntactic sugar, in my opinion. Granted many of Haskell's operators are also common, but I wish they'd been able to limit the variety a bit.