From what I've asked people, the complaints fall mainly into two categories:
* familiarity and aesthetics. Rust uses fewer round () parens, and more <> and {}. This makes it look alien, and people say it's unreadable when they don't immediately recognize the language constructs they know.
* misattributing difficulty of learning Rust concepts like lifetimes and generics to their syntax. People say they want less syntax, but they mean they don't want to explicitly specify things like ownership and trait bounds.
* familiarity and aesthetics. Rust uses fewer round () parens, and more <> and {}. This makes it look alien, and people say it's unreadable when they don't immediately recognize the language constructs they know.
* misattributing difficulty of learning Rust concepts like lifetimes and generics to their syntax. People say they want less syntax, but they mean they don't want to explicitly specify things like ownership and trait bounds.