I mostly play the 4231 and I like one of my CDMs to be an out-and-out CDM, so I use Kante, but I like the other one to be more of a box-to-box one on Balanced Attack so I can score some finesse shots from outside the box. So for this purpose, I looked at all the possible options in the game, and after Gullit, I thought Ballack's card had the best stats for this role, to attack as well as defend.
I use him with an Engine chemistry style to boost his agility and balance, which looked like the only cons. Tried him with a Shadow and Sniper as well and preferred Engine.
Pace (7/10): With an Engine, he has about 85ish pace. Doesn't feel slow, doesn't feel fast either. It's just in between. Sufficient for a deep position, no complaints.
Shooting (8/10): It's great. Finesse shots from outside the box with both his right and left foot go in. They don't go in every single time though, he sometimes hits the post. But they're mostly on target at the very least. Long shots where you just power up and bang it are a bit inconsistent, which is strange because he has 92 long shots. I think this might be because of his rather average dribbling, which I will get into. Some people have said his long shots are great, but I personally prefer to finesse them when I can with him.
Passing (10/10): His biggest pro. He is legit one of the best passers I've used in this game. They just go exactly where you want them to. As a second CDM who does attack but from a deep position, I like to pass it off to my CAM or striker and he makes no mistakes. Rarely loses the ball.
Dribbling (6/10): There's no sugar-coating it. His dribbling overall isn't great. He is a bit clunky but with an Engine he becomes very usable as long as you play him CDM/CM. I don't think he's agile enough for a CAM because you don't want him getting in behind and losing the ball which he will because he's clunky. His dribbling and ball control are excellent when you're not sprinting, but when you're sprinting with him, you'll have to be a little careful. Don't try to dribble past players with him, it's not going to work, pass it off if you encounter traffic. I wanted to compare him with Pogba because Pogba has low agility and balance too, but when I tried Pogba, his dribbling was far better. That low balance stat on Pogba has to be a lie. However, this was the only area where Pogba was better because Ballack was better at everything else, especially shooting.
Defending (9/10): Great in defence. Tracks back, bullies players sometimes. Would've given him a 10/10 if he was a little quicker. Tall, so wins a lot of headers.
Physical (9/10): Felt like his stats suggest. 85 strength, he bullies players but not every single time. Can hold his own. 88 stamina is great. If you go into ET, in the second half of ET his stamina drops into orange, so is a slight concern. But hey, you can't expect better than that.
Overall I'd give him a solid 9/10. Only real con is the agility, but that's what separates him and Gullit. And Gullit is significantly more expensive and not everyone can afford him.
If you're expecting a midfielder that makes runs into the box and scores, he's not ideal because his dribbling isn't good enough to beat players. But as a deep playmaker that assists and scores finesse shots from outside the box, he's excellent.
I don't believe he is a card for everyone, so make sure you try out his loan before you get his full version.
Finesse shots with both feet
Inconsistent long shots