Arsenal had a productive summer transfer window as they signed four first-team players, but this number could have been even higher. Defender Riccardo Calafiori and midfielder Mikel Merino joined on permanent deals, whilst Raheem Sterling and goalkeeper Neto joined on deadline-day loans. Transfer expenditure was not as high as in the previous year, but the squad is stronger, with Calafiori settling in particularly quickly. Arsenal could have added to their front line as several wingers and strikers were linked, but Mikel Arteta kept faith in Kai Havertz, who has started the season superbly. Ne…