It is a big problem that so many standards, requirements and tools (from EMACS to Coverity over lint) have their fingers in the C-syntax. The autocrap abomination is a further complication.
So I guess a good place to start is to swear that we will never touch or use the botched ISO-C thread API, and beat some sense into the WG14, by whatever means are available.
A long period of stability may also make it easy for C to interact with other languages. I'm out of my depth here. Some standard specifications for pinning memory from garbage collection, if Scheme could specify TCO, perhaps C-consolidation release could improve its toolability for things like Coverity; A better autoconf; Makefiles; Standard compilation error codes; Something that would clean up all the rough edges in supporting C compilers.