I went to both the Friday and Saturday games (I have a 20 game season ticket package). Attendance on Friday was bad, the game was never competitive, and there was absolutely no energy in the park. On Saturday, the attendance was a bit better, the game was very competitive and fun to watch, and there was a lot more cheering and enthusiasm from the crowd. Much better atmosphere. So, for all we want to talk about "experience", it really does depend most on the quality of the game.
I haven't experienced the A/C problems, unless you are talking about the wind tunnel effect in the top few rows of the promenade sections. Beyond that, I haven't experienced any temperature issues.
Finally, concessions are overpriced but not terrible. As someone said, there are two "value priced" concession stands. And, anecdotally, the refillable, souvenir sized soda is $8 but is $12 or $13 at Dolphins games.
I don't really see what Jeter and Company can do to improve the experience other than put a better team on the field.