Merino is going to really be a good addition to Arsenal,and with the sale of Smith Rowe already from the club,Merino will be a very quality signing judging from his performance in the Euro.He plays a similar pattern of football like that of Granit Xhaka who left the club last season and the club had struggled to get a replacement for him.
Merinos signing will really boster Arsenal's midfield,and couple with the fact that he will operete from the left flang,it will make Martinelli or Trosard get more goals next season.
Arsenal have recruited two quality players in this transfer window where they previously managed to bring in Riccardo Calafiori and Mikel Merino, of course this is a pretty good signing to add to their strength. The defense line became stronger with the arrival of Calafiori because he is one of the defenders who is strong enough to break attacks. Apart from that, the midfield is also getting stronger with Mikel Merino joining because he will be a pretty good tandem for Declan Rice.
Arteta is doing a pretty good job on the transfer market, he knows which players are suitable to recruit. We are just waiting for a productive striker to maximize the strength to be more perfect this season.