Such an interesting case, but one that can provide nothing but frustration as we'll simply never know.
While it's very easy to say you'd never leave your kids for more than however long, I think people underestimate how close the restaurant was to the room. Plus there were hourly checks. These checks were made on rotation by the group, so this surely rules out any idea that Madeline was dead "days" before the missing date (one theory).
The evidence of "blood" and smell of "death" in the room from the Police dogs is interesting, as is the dna match in the hire car. Unexplained situations.
But I've always thought the most likely version was the abductor story, and now the abductor is dead themselves. There were a number of seedy characters in and around the area, a couple who are now dead.
Talk of "Over dosing" her seems ludicrous. This is doctors we're talking about here. You'd need a tonne too high a dose for that.
And talk of some elaborate cover up, managing to do it, hide it from their friends who were helping carrying out the checks, and then managing to get rid of the body all in a small time frame seem to ask for pretty epic levels of stealth.
The Portuguese investigation seemed a bit of a joke as well, one investigator coming up with outrageous slurs against them, and getting kicked off the case, and sued.
Some of the McCanns comments and soundbites are a bit off, but if they've just had their daughter stolen, how should they act? Most likely you'll be all over the place.