I think old football players becoming coaches is not a good idea at all, I mean maybe Lampard because he was always a smart player but if you want to look at good coaches you will see that not many of them were star players ever.

Mourinho is known for not played at a major league at all, only trials and so forth, Klopp wasn't a big name neither, even pep was a decent player but not a star, if you want to look at great coaches most of them are players who have retired early and got into coaching early as well because they knew they wouldn't be players wanted at age 35 so they start early, Lampard wasn't like that many new coaches who are seen like promising future will be a let down because they played instead of coaching in years the other ones started coaching already.