The simplest fix would be to raise the bar for becoming a dive professional. Nothing else needs to change. And while that might increase costs overall for dive ops, it would have no impact on #1 & 2, and would significantly improve the diver experience overall.
... Bob (Grateful Diver)
It seems to me that the person signing you in for your dives and checking C cards is not always a dive pro at all. They're often just a shop/boat operator minimum wage employee. So, I'm not sure how raising the bar to become a dive pro would really help.
If a dive operator is filling their boats and they are occasionally excluding an over-qualified diver, I'm not sure the dive operator would even agree that there is a problem to be solved.
If a dive operator is actually denying seats to people for lack of a paper dive log with a signature, that seems to me to be a problem that a free market will solve in due time without any help.
Beyond that, if you're going to do dives for which you are highly over-qualified, it seems like it has already been said: Recognize whom you may be dealing with (i.e. a minimum wage employee whose job is to check for a Nitrox card) and don't expect them to be so well-educated that they recognize that a Trimix card is really a Nitrox Plus Plus card. Save yourself the headache and just take an extra card or two (e.g. an AOW card and a Nitrox card). Or stick to doing truly advance dives where the dive operator WILL recognize the higher level cards as they are specifically looking for those.