You may be a little surprised by this response, but I don't altogether disagree with you.
Ultimately, the McCanns were exonerated, which clearly they wouldn't have been if there had been a mindset to frame the McCanns.
As I've pointed out elsewhere, it is considered a legitimate police tactic to put psychological pressure on suspects to try to make them crack: the rationale being that if they have nothing to hide, they won't crack.
And there was some genuinely fine work done, much of it on the Portuguese side. PJ Inspector Dias in particular was very astute. And witness statements, taken by Portuguese policemen, went a long way to establishing that neither the McCanns, nor their friends, had anything to answer for.
In the very earliest stages, I think those Portuguese dog handlers were a (genuine) credit to their profession.
The Portuguese prosecutors deserve mention, too. They were even-handed and fair ...
So yes, I think a great deal that is credit