This spec mostly concentrates on simplifying the syntax of numbers, but it does not do anything about one of the big omissions in JSON: it does not specify the range of integers or the precision of fractions. There are a lot of interoperability problems in that omission.
(The other thing SON does is require unique keys, which is a good improvement that fixes an interop bug that can cause security vulnerabilities.)
(The other thing SON does is require unique keys, which is a good improvement that fixes an interop bug that can cause security vulnerabilities.)