An example of the streamlined reduce-the-clicks nature of the new UI is the tactics screen, which has merged the match preparation section into the main page now, and things like Team Instructions, Set Pieces and so on are all in the ribbon above the main section. It'll take a while to get used to where things are, but once you do, it's better than the old system.
There's also a system to help reduce the need to constantly readjust the in-game shouts you'll apply during various situations. Now you can create your own ones that will combine lots of different commands into one uber-shout. Like you were using a megaphone on the touchline where before you had to use smoke signals.
Most of the changes have come off the field, but what about the engine itself? On the surface, it's got slicker, with more animations giving the players a stronger, more physical feel on the pitch, and there's a director cam that changes angles every so often to provide more of a diverse viewing experience to matches. It only really changes for set pieces, but it's a welcome addition nonetheless.
Poking around underneath the surface reveals an engine that's received a lot of tweaks from last year, so you won't be scoring quite so many goals for corners. You'll still create (and concede) a good deal of goals from set pieces, but it feels better than last year in that respect.
You'll also need to relearn what makes the game tick too, because your first forays may well be of the "Huh? I couldn't even beat my reserves?" kind. You might actually take more interest in your reserve and youth teams this year, because you now get to control the youngsters that get inducted into your u18s (or whatever the equivalent is in the league you decide to play in). It's a really good addition, allowing you to pick and choose the exact players you want to strengthen your youth, and also to avoid getting a load of complete wasters.
Training these young guns up is the same, basically, but this time you chat to the coaches about changing their preferred moves instead of asking the players themselves if they want to. The players can also issue comments about things other managers say, so for example Mario Balotelli might take offence that 'appy 'arry at Tottenham said Man City weren't capable of winning the title. You can also respond, but you're still too restricted on what you can talk about, which is a shame.
There are far too many other things to discuss and a lot of them get noticed hundreds of hours down the road. For example, only a day before submitting this did your reviewer here notice that you could hold team meetings - thankfully you can use the improved tutorials to fill in any blanks if you do feel like you've missed anything.
So anyway, it's FM like all other FMs. It's painfully addictive, screen-shatteringly frustrating at times but so moreish it's like the computer game equivalent of Chocolate Fingers. The improvements are significant without breaking the fundamentals, and it seems that Sports Interactive has thought long and hard about how it can implement changes that would bring back the disillusioned without enraging the devotees. Roll on FM 13.