Strongly agreed. strace *is* a crufty old goat that would be nice to replace, and anything that can put ptrace() uses to death is a good thing in my eyes. But we do need argument decoding if we're to use it to figure out what on earth a program is up to, which is, y'know, the point of it. AIX has a syscall trace program that doesn't do any argument decoding (even of strings!), and it's main use is as a source of frustration (though of course it doesn't do any of the other things trace does either). Kicking up the debugger is often easier, even without debugging information.
(I know that argument decoding is really boring to get right and tends to involve giant tables of syscalls so needs active maintenance, but unfortunately it's also hard to avoid for a useful tool. But, hey, if you don't actually object to it so it might turn up later, that's fine: we know there's nothing in the implementation that makes it harder for trace than it is for strace. At least you don't need to worry too much about putting new syscalls in fast: the new syscalls will be relatively unused for a long time, so you don't need to rush to add them to the syscall table in the tracing tool.)