Yes you're right Ratmonkey, it is slow and it seems rather clunky at first so it would appear to not seem that useful at the start but the important thing to know is that these elements of close-control are situational and understanding when you can use them only comes from experience (and that's not a dig at you btw, keep reading).
Personally, I initially hated how the tricks where implemented in 15, I thought it was a sloppy break from the previously 'clean' methods of getting past players (as done in the previous titles.)
For example in 14 I knew that I could perform a given trick secure in knowing that once executed the animation would lock the physical scenario allowing me to pass the on-coming player clean, so tricks and flicks effectively guaranteed a 'clean' outcome.
This isn't how this is achieved in 15 and initially it was something that really upset me for I began to think that tricks where useless because when I ran through the motions (pressing my usual combinations) expecting to simply stride past defenders the AI player would simply step back and wait for the trick/control animation to end and just take the ball off me at it's conclusion, well this was just infuriating I was often heard screaming at the screen "WTF!!! I'm doing the tricks and they aren't working ....Tricks are useless now!!!
But then through playing more and experimenting with the different game modes I began to understand the conditions and contexts for when the control shifts and close-control tricks can be made. So if done wrong you gain nothing but when done right you gain that bit of space and that's what I love about 15 now, there is a skill in understanding when you can turn the AI inside out, and just as in real football it doesn't always come off but given the correct conditions you can really bamboozle the AI in consecutive strings, almost as if you are achieving combos (if it was a fighting game), and again this takes the knack of understanding of context and timing which I believe has really added an extreme level of depth to the game (whether or not it was intentional). It's not clear cut - it relies on moments when you feel the defenders will over-extend or try to pressure you harder and therefore are drawn closer to you, and it is this area where the magic begins.
Just as I stated to a friend when talking of the game, I said "every time I play 15 I'm learning more." that still applies.
..and everyone is different, so not all players will understand and experience this level of depth but some will. Like my friend for example, he scores the same linear goals over and over (and loves them!), he never creates forward runs with off-the-ball players ahead of him (the L1 + R-stick<-- ability) and never ever sees/understands that peripheral area (just off-screen) where your attackers dwell nearing the offside zone where feeling will tell you when that perfect time is to deliver a through lob - he just sees what is close and visible to him, similar to his ignorance of the radar and he also doesn't know or care to know about the tricks or close control (personally, I think he misses out on so much of the game, as there is so much to his game that he just doesn't improve on). But still, he loves the game nonetheless, but my point being that not everyone will delve into that level of understanding, particularly on close-control, which for me adds so much to the satisfaction of the game.
I guess in real life I'm a creative player too so perhaps it rubs off and maybe I see stuff he doesn't but it's great that the game caters for both.
Sadly, in 16 that depth is gone, the combinations don't work or skip and don't make sense - the whole experience feels a little light and rushed, as if the depth has been replaced with a simpler system. But again that's just me, and in ending I haven't spoken to my friend yet but I'm sure he'll love 16 just the same, though he's always been more direct than me.
But it's fun to do a few times in a match.