For instance, we added the '_Bool' data type and require you to include <stdbool.h> to spell it 'bool' instead and to get 'true' and 'false' identifiers. This was done to not impact existing code bases that had their own bool/true/false implementation with those spellings. Now that "enough" time has passed for legacy code bases to update, we're looking into making these "first-class" features of the language and not requiring <stdbool.h> to be included to use them. We're doing the same for things like _Static_assert vs static_assert, etc for the same reason.

For example: removing the register keyword, always requiring a return statement, etc etc.

A lot of changes can me made that will make static analysis easier.

There will always be people with 50 year old code bases that will never change (and some c89 compiler will always be there for them), but the language is pervasive enough that it deserves progressive changes to make it (even) simpler and safer and slightly more high level.

Just #include <stdc.h> and be done with it. No need to remember stdio, stdint, stdbool, limits, assert, signal.h, etc, etc.

This new header comes with a guarantee that use of identifiers in the standard-reserved namespace will break your code. Perhaps compilers could even enforce this preemptively.

Note that by including the content of all the headers, you're increasing the chance for collisions with application identifiers. You might consider that more of a benefit than a drawback.