TBH I personally don't think Hakan is the same as Brozovic; like Hakan had been playing well, but what he did was somewhat different.
To elaborate, Hakan is very good at transitioning from defense to counter, tearing defense and excel a lot when we are in a fast tempo, but Brozovic is better at controlling tempo and keeping possessions, nullifying pressing and move the team forward up the pitch, which you see the way we attack are very different with Brozovic or Hakan in the regista position. In short, we do more sieging with Brozovic, and this leads to more stable plays, hence maybe one of the reason we are conceding more this season, cause with Hakan we are trading quick attacks more.
Plus Brozovic is better at defensive duties as well.
Kessie is good for us, but he is more Barella role to me, but we can always change the way we play.