I had this happen yesterday.
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My central defender Leigh Franks made a terrible mistake in the first half leading to a goal. At half time I used the aggressive "I am not happy" talk and he ended up making some great stops, a great assist and shut down most of the corners with great positioning and heading. He went from a half time rating of 5.2 to 7.8 at full time.
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As you can see there nothing that special about him. His personality is "Spirited" and I'm listed as his favoured personnel. I'm not sure what it is about this guy, his attributes aren't great, but hes a great player in my system normally with an average rating of 7.6 over 31 games.
So I think some players can really turn around their performance in a match, but I would say they are exceptions to the rule. I would only trust this guy and maybe one of my other players to have a terrible first half and come out playing at their best after the half.
(Great guide overall, I was using almost the same approach as you before I read this. It does feel a little dull following the same formula all the time, but you can't really beat it for raising morale. Becoming favoured personnel with your players helps a ton too!)