That was a good read and good analysis about the state of the program.
A lot of good stuff has been posted already, so won't repeat anything, but a few things to add that hasn't been mentioned:
1) Mullen came here promising more points on offense, saying that when Florida is at it's best, we're scoring and having a high-flying offense. On that, he's delivered. I didn't really like Franks as a QB, but Mullen used his strengths and we did improve our production on this side of the ball. Three years into the Mullen reign and Florida has definitely been a premier offensive team.
Why is this important?
Offense wins championships in this day and age. Even Saban/Bama have recognized this and adapted. The most recent SEC shorts video even laughingly mentioned this, with the A&M guy saying "if 2009 Alabama could hear you know" and the Bama actor saying something to the effect of "adapt to survive." It's true: defense is still vital (our lack of even a serviceable defense cost us a shot at the Playoffs and more victories); but it alone won't win championships anymore.
Mullen has proven himself an elite offensive mind (the breakdown of the UGAy game was excellent in highlighting his schemes); now he needs to evolve and add in overall program management.
2) Mullen's recruiting has been subpar. It was a big reason I wasn't sold on him as the hire when it was announced; and he hasn't covered himself in glory there, as none of our classes have been top 5 and that puts a severe handicap on what we can accomplish. Granted, he's improved things slightly above the Chump/Butters years (we're getting 4* instead of 3, etc.), but not getting enough of the can't-miss 5* guys that directly lead to championships.
What I will acknowledge is that for all his failures on the actual recruiting front, he's done a pretty good job picking up highly-rated transfers. Greenard, Van Jefferson, Grimes, Cox and Shorter have all been difference-makers in the past two seasons (before anyone jumps on this *cough* Donkey...Cox/Shorter are at the bottom of this list for a reason...). It's not insignificant and hitting the transfer waivers hard has brought in immediate production on both sides of the ball. It's what we ask/expect of a head coach at the end of the day. Sure, recruiting makes a huge difference, but if Mullen is a top 3 coach at selling/closing inbound transfers then that counts for something.
To conclude on a point *everyone* seemingly agrees with: Mullen needs to make a few changes this offseason. We aren't far off where we need to be, but it's up to him to recognize and learn. Grantham is a dud. His schemes throughout the season did more harm than good and he utterly failed to put his players in position to succeed. He absolutely needs to go, as we're not winning anything, ever, with him as a DC. That much is clear. He also needs someone to help with clock management, since this is a recurring issue. Go to the AD and ask for money to hire an asst to fix this. It's cheap at the price if it adds a win at the end of the year to our record (and there's at least one game every year we could have won with better time management).
Our problems are correctable IF there's a will to make the tough changes. Mullen's earned himself some goodwill here and I'm fine with giving him another year to see what he does since he's admittedly brilliant on the side of the ball that we need to be successful at in the modern game.