It is your job (manager) to utilise those people and get the best out of them.
Why do you think he is not getting the best out them? They cost f*ck all. Maybe occasional bursts of speed and skill is the best these players can do at the moment.
I used to teach A level. There were some weak students who in the 2 years I had them, I could not get them better than to an E or D grade no matter how inspirational I was, or how many different exam skills I taught them.
Levein has a bunch of cheap, therefore 'weak', footballers. Maybe some of them are going to take 2 or 3 years to reach B or A grade no matter how inspirational or technically skillful Levein is with them, or possibly most other managers as well.
Levein was not given the money to buy 10 A grade footballers.
Support Levein and his footballing 'students'.