It makes perfect sense. Remove the rule and its the yellow cards that have no sense. There's no point of booking the players if it has zero impact. Same with wiping the bookings at any stage. If someone got the yellow , tough luck,he propably deserved it.
Ref making a mistake is a completely different issue. They should just thoroughly review all the cards using video replays, but that propably wont happen within our lifetimes.
Again you ignore the fact they openly stated it was too harsh, and have changed it for the Euros, and are considering a change for next year. What seems to annoy people is that if you have changed it for the Euros, why not change it for the CL this year?
And it would still have an impact. Just not one that is overkill.