Any attributes or keywords relating to Objective-C or interop are not everyday baggage for most people.
For SwiftUI, attributes seem like as good a choice as anything else.
As a whole concurrency is a mishmash syntactic mess, but I agree with the direction and the result, they're trying to manage the improvements they keep adding over years of investment.
The number of keywords in Swift is not an uncommon criticism . Even Chris Lattner is critical of the direction Swift went in after its inception. I'm not sure what you're referring to with "order matters," but SwiftUI's issues go far beyond the order of the modifiers used.