I'm not a massive massive fan of Allan, if I were going to go for 1 player from Napoli it would be Koulibaly. That being said, it's clear Ancelotti obviously likes him and he has worked with the Napoli squad and knows all about them. It's also the case that our weakest area, by some distance is midfield. Gomes sticks out like a sore thumb, but he is also erratic and inconsistent.
I dont think Allan is a hard man either. Hes an all round midfielder and would be well suited to playing in a 4 4 2.
As a final point, let's be fair here, Napolis players are levels ahead of where our players are. So if the fee is right, with all of the above I'm happy with it. He might provide what we hoped Delph would.