Basically they have tweaked the training section (which is good), that needed to be bolstered a bit more and be a bit more user-friendly for the Football manager newb.
They have upped manager AI. So players and managers can fall out, and / or a player's attitude can quickly change pace.
Ref Stats are good. This will help in your tatics. If he is soft, you could set your players to hard tackling and try and test his patience as it were...
What, I would like to see however, is going a step beyond...and bringing realism to a whole new level...
* Match-postponments (hardly ever happens now, but used to...)
* Match-abandonments (for whatever reason, rowdy fans, weather...)
* Players failing drug tests and getting bans (a la Rio)
* Players getting lenghty bans for violent conduct (a la Cantona) - which did happen once in a blue moon on the old CM games.
* More freaky and realistic weather patterns (see no 1.) Before I installed a Russian patch. Games in Moscow would be 6C in November!

* Players going AWOL (does this still happen after CM4?)
The half-time team talks should be fun. I like the idea of being able to bollock your players after being down 2-0 down at HT. This should also help shape your manager character.
I want the media thing to be expanded on too. I think the "pyschological war-games" was a good thing - but could and maybe should be incorporated into a post-match press conference.
Basically, you should be able to load up a screen, and get questions fired at you. And the responses you give, shape your manager style and how the players and opposition view you. So, you could come out and defend your players at all costs, like Wenger or you could blame the ref continually like Allardyce and get fined by the FA, making lots of enemies.
If you talk badly of a player he will get upset and conversley be happy when you praise his hat-trick against Chelsea...
How cool would that be?
I like the idea of beating Manchester United at Old Trafford and sitting there, with a beaming smile prasiing my players whilst scoffing at Man Utd in front of a press junket.