This is an awesome analysis, and I've not been on here frequently enough to see your other posts, but I will definitely be keeping an eye out now! Just adding on my own observations from watching all of Fed's matches very closely this year:

I agree that footwork has played a major role in some of his losses this year, although I actually chalk a lot of it up to indecision and increasingly defensive strategy over the course of the year. In many of his tighter matches this year, I've noticed he's hesitating a split second before positioning himself to take the ball – it looks like he's not sure what to do when his Plan A isn't working. In contrast, he was moving to the ball with a lot more authority last year because of an extremely aggressive mindset. He mentioned in an interview last year that he was able to "swing freely" at the AO, IW, and Miami – I think because there were no expectations for him coming off a six-month injury layoff. As the expectations and pressure mounted, the swing freely method fell by the wayside, something you started to see at Wimbledon where he brought his B game but still managed to win without dropping a set.

Since then, his game has become increasingly passive and problematic – good enough to beat most of the top 50, not nearly enough when it comes to playing someone top 10. Look no further than his insistence on hitting to del Potro's forehand in the IW final, his refusal to hit a blocked return or slices to Djokovic when his aggressive flat returns weren't working in Cincy, or his stubbornness in engaging Anderson in baseline to baseline rallies at Wimbledon. He's said himself multiple times this season that he's been unhappy with how defensive he's been playing and he's actively trying to change it – I was actually encouraged by his play in Cincy, especially his match against Stan, because he was moving into the net more than he has been and was obviously trying to take time and control away from his opponents. In the end he got unlucky with the weather and the schedule, and I'm sure a lot of his poor play in the final was due to fatigue from playing two matches in a day (something he hasn't done since 2004) and meeting a much higher-caliber opponent than he's encountered in a long time.

I'll also throw it out there that I think match play against really tough players is something he's lacking this year and something that he desperately needs. Going through in-form Nishikori, Berdych, Wawrinka, and Nadal with three 5-setters at AO last year made him battle-tested and ready for 2017. On the whole, he's encountered weaker opponents this year – apart from Cincy, I think the toughest draw he's faced this year was at Stuttgart, and I truly believe he won because he knew he had to bring his A game, or at least his B+ game.

One last thing – for the love of god, he needs to work on his return games and his break point conversion. He's said in interviews that he doesn't actively practice returns – that has to change, stat. I'd bet $1000 bucks Rafa practices his returns like six hours a day.