Not for builtin PHP functions which already throw errors on arity mismatch.
> this would literally break class autoloading in symfony, and even the engine itself, which relies on this feature
I don't understand. Could you point to where in the Symfony code it relies on being able to wrongly call a function with more arguments than it expects and will use?
For variadic functions there is the ... operator already in the language since version 5.6, and my proposal wouldn't break that. Also note that builtin functions already emit deprecated warning in PHP 8 when called with too many arguments.
Here is the full thread discussing it on the PHP internal mailing list: https://news-web.php.net/php.internals/122928