Everybody and their uncle have an idea about how they would "fix C++" - but these ideas mostly contradict each other and would make for rather different languages :-)
I think C++ could really use what Rust calls generations. Figure out the obviously bad ideas and deprecated them over 10 year cycles.
That would allow the language to shrink again, I don't think it ever did.
Even things like integer promotion rules or "trivial" things like "deprecate NULL and 0 for nullptr" are likely untouchable with any edition mechanism for C++ that doesn't end up Breaking the World.
Regardless - C++ will effectively has some deprecation, at least of the standard library, with the introduction of modules instead of included headers in C++20.
Everybody and their uncle had a lot of ideas about how they would fix "C++". Eventually all those contradicting ideas got merged into the C++ standard.
:)