I don’t think when they established the 12 regenerations rule, that they realized the show would go on as long as it has. It’s been shown in the classic show that The Master got around these boundaries, and I don’t think there was any big plan leading up to the final incarnation, seeing as the rule was established nearly 40 years before the payoff. I don’t understand this complaint at all.

It was not his place to tackle the problem.

Then whose was it? I’m just glad it was addressed at all. The other solution would be to simply ignore it. Ending a popular show because an earlier episode decades earlier made a silly rule is simply nonsensical.