Even if Fred is not necessarily the replacement for Fernandinho I think he is a very good player and be a great player to have in the squad.
Fernandinhos athleticism, game management, presence on the pitch, understanding of what Pep wants in the various stages of the pitch amongst other things is what makes him so vital and almost impossible to replace.
For years we stuck him in a team that required him to do about 3 jobs, now he has one and the one he is good at then we are all seeing how good he is.
Fred comes across Asmara someone who wants a move, something to take him to the next level. Exactly how Fernandinho was a few years back.
Weigl is very talented and is struggling in a disjointed Dortmund team, he simply isn’t a replacement for Fernandinho however