Morata has never been an incredible scorer in his career. In terms of this aspect he is overrated. However he can still be supportive on attacks in an effective way. But I don't know playing as the centre-forward at Milan would be good for him. Pioli uses a 4-2-3-1 formation most of the time. I think Morata shouldn't be the only player on the front to be relied upon.
He can be more effective when he has a companion beside him. I wonder if Pioli has such plans to make a change. Because I don't remember him using a formation with two strikers. But if you have Morata in your team it is better to adopt such formation just as Atletico Madrid have done.
Morata was once the lone striker in the Spanish national team and that went well in my opinion, in terms of quality Morata is a player who is quite agile in his movements and takes up empty space.
I think Morata won't be a problem if he gets good support from the flanks or in the middle to score goals, Morata is the type of player who can be an executioner and can also be a good feeder for his teammates, for a striker he's not selfish and that's very good for the team.