That's well-put — only, User:197.86.143.126, I'm not sure you're actually engaging with a position anyone is arguing for. I don't think anyone has been proposing to cover the Cushing movies solely as in-universe fiction. The question has been whether the coverage of their content for its own sake should be done as {{invalid}} or not.
So do you agree with the proposed scheme of making the Cushing movies as valid as, indeed, the Polystyle comics, or Doctor Who in an Exciting Adventure with the Daleks — regardless of the business of his possibly being in-universe fiction? Or is your position different from this?
Incidentally, you're not allowed to link to YouTube videos in the forums of this Wiki, for complicated procedural reasons. If you want to refer to a video which cannot be uploaded to the Wiki in earnest, you should give us its title and channel, and leave interested readers to look it up for themselves.
(Also, the "Morbius Doctors" are not covered at Morbius Doctors but at The Doctor (The Brain of Morbius). And arguably, it's not The Deadly Assassin which made them difficult, but rather The Caves of Androzani — there was no reason not to think Tom Baker was playing the twelfth incarnation of "Theta Sigma", albeit only the fourth to use the alias of "the Doctor"; indeed, the fact that his contemporary the Master was on his last life in Deadly Assassin suggests this may well have been the intent. …But all this is really neither here nor there. Later narrative discontinuity is irrelevant to these discussions; what matters is intent at time of release.)