FM2016 how deep is it? What do you control and what do you really love about it?
FM2016 goes as deep as you want it to go. You become a Manager of a Football side you choose in just about any league in the world, from the smallest of amateur leagues all the way up to the clubs in the biggest of the professional leagues. You hire and fire players, staff, you dictate what tactics are used for each game, and for each player in a game, you set up the training schedule (or you can hand it off to an assistant) for the entire team as well as for individual players, you send out scouts looking at your next opponents and to find new players.
You also have to manage your team and the personalities of your players, including how much on field pitch time they receive, whether to send them out on loan to help them develop or whether to sell them.
You pretty much have complete control as long as you satisfy the requirements of your club's board who each season will give you requirements to meet. Do it and you will be secure, don't and you may get the sack.
Only thing you don't control is the players once they step on the pitch. It is not like FIFA or Pro-Soccer Evolution where you control the players with a joy stick.
However as I said earlier, you set the team tactics, and the tactics for individual players, which you can tweak during each game. Even small things like what kind of pre-game and half time team talks can impact on how your team performs. You can set the actual game to only show "highlights" so you don't get bored watching the players running up and down the field.
As such you can look to manage your favourite club and try and build a reputation ala Sir Alex Ferguson at Man United, or be more of a wandering coach for hire ala Jose Mounhino. Some people take their club form the lower divisions and try to get their clubs into the op level.
You even have to negotiate with your board for some things (e.g. Stadium expansion, transfer/wage budgets).
Whilst they have a licence to use real player names in the game, they don't have licences to use all the kits and logos, but there are plenty of easy steps you can find to add them to your game.
I've played plenty of Sports Sims and the football Manager series leaves the others for dead.