Deprecate the bad stuff (see: throw specifiers, auto_ptr).
Write tools that help people program in the modern subset (see: clang modernize).
If the answer is practice, what daily tasks come into your mind first of all? It's possible to have both, and I think the modern style of C is quite close.
Some developers think that C include too much poorly compatible features, that language is exaggerated. If you were creating a language from scratch which existing features you would not have included?
Is there a chance that some parts of modern C in the future will be declared obsolete and deprecated? Some are from it's C legacy, like the declaration syntax.
C is sometimes criticised for being a very discrete and abstract, almost Spartan, Standard Library. The criticism is fair: the Standard Library needs to be greatly expanded. I have never heard this view espoused in the Committee.
It doesn’t have a variety that other modern languages have. I want: Unicode support, databases, date/time support, serialization, networking (with support for lots of different protocols), parsing, etc., etc. Creators of the original standard library think that it should be small and atomic, and everything else should be in a different library, not in the language itself. Folks there are eager to expand the Standard Library.
In it's place, I would prefer an AST-based, hygenic macro processor.