When West Ham hired Manuel Pellegrini as their manager in the summer of 2018, there was a huge wave of optimism among the club's fans.The Chilean was an attentive Premier League-winning manager with Manchester City and former head of Real Madrid. What can go wrong?When it turned out, a lot. Performances were largely promising during his first season in charge, and there was an obvious transition to a more patient, ground-based style of play. It was OK. But his follow-up campaign, which ended shortly after Christmas 2019,…