This is a strange list. The reasons for putting off generics have been made very clear. Fast compilation and simpler syntax are not unreasonable tradeoffs to make in exchange for waiting for a fast and simple generic syntax.

And your argument against multiple return values makes no sense. How is using a tuple type better (or even different, in practice)? And your pointing to the mathematical definition of a function is pointless. A function has a very different meaning in programming languages than it does in mathematics. Mapping a domain to a single co-domain is not what functions do in the vast majority of programs.