This is potentially a great signing, or another waste of money. There are countless instances of exciting youth players in PL clubs not fulfilling the potential that was originally hoped for - the lower leagues are littered with them.
In some cases I believe that the reason for the lack of ongoing development is down to a combination of both football AND PERSONAL guidance. Being a top footballer these days requires a level of commitment to the job that you would have been laughed at for giving in the 'crazy gang' era. In fact Bradley Dack acknowledged that without JE's guidance WHICH HE TOOK ON BOARD he would not have achieved what he has done.
So now it's up to Willock, whether he's willing to put in whatever level of work and commitment necessary in order to fulfil the potential that evidently knowledgeable people saw in him when he was younger, and hopefully work his way back up the leagues.