>Knowing what each syscall does isn't really the hard part of strace, it's knowing which ones are important, which ones are part of libc itself and can usually be ignored

An excellent point!

More broadly, since many/most Linux/Unix/etc, programs use one or more libraries (which in turn could use one or more other libraries, etc., etc.), then one very important key for designers of any type of strace program, present or future, is:

Can the traced system calls be set granularly, such that the individual libraries making syscalls (as opposed to the main program!) be identified individually, and possibly filtered in/out from the results accordingly?

So, an excellent point!