The PID is used for more things than just shininess (gender for sure and probably initial ability / wurmple evolution too, unless I'm totally wrong). Spinda spots are now believed to be based on the encryption constant (no need to decrypt PKX to make spots).
Good luck getting poses and generating an egg to get the 32 bit value. We don't even know if it is modified in any way, or if any RNG advancements were to occur.
It's best to find something with a multitude of repeatable random responses; the more the better.
In the meantime there's a few better things to do than get your initial RNG state; we have no way to know how it is modified or used when generating Pokemon if we cannot see the raw data in-game. Hence why battle video uploads (to check breeding inheritance/pid/ec) or total dumps are a higher priority.