Tony Kroos can be an interesting search for Manchester City. You know he is still a great player, even though he is thinking about his retirement. And I believe he is definitely going to perform well even though he is not very young anymore. Yes, I also think that Manchester City will be able to use him properly.
Don't get me wrong, I am not saying Real Madrid is using him badly. If anything, Real Madrid is using him the best. But as he is already thinking about retirement, it will probably be a good journey for him to join Manchester City and achieve something with another club as well.
I doubt Pep would give much thought about bringing in Toni Kroos to the club. He’s no doubt a superb player with a lot of experience under his belt. But like you noted, he may be thinking about retirement having had a successful career.
Despite being an experienced player that could boost City’s squad, I doubt Pep would spend some good money in bringing him in only to have him play one or two seasons.
I bet the Saudi league would be pooling in money in a bid to attract him to come over whenever he leaves Madrid.