I disagree. A different manager, doing things differently, potentially could get more from the current squad. The combination of an Inexperienced manager and mostly inexperienced squad may be the problem. You have to have a high level of emotional intelligence and understand what motivates each individual player to get the most from them.
Absolutely no doubt that Marvin talks a good game. But not convinced that he has the capacity for enough flexibility or empathy with the players. He seems very rigid and inflexible to me.