It will be very difficult for him to win the Premier League, but he has a strong attack (Sanchez-Lacazette-Ozil) and without the champion's league he can focus on the Premier League.
They are not as good as the other player from the other club but they are outstanding player. They are not going to win the league with just the three of them because arsenal has poor defender . Even if they have a great goalkeeper, with their poor defender it will be very hard for them to win the league
Arsenal may not playing in Champions League, but they will play in Europa League, and We all know, Europa League match schedule is very narrow with schedule of League match, And sometimes when away match which far in europa league, very impact on team performance in league because of fatigue factor. So even though the opponents in the Europa League look easier, but the europa league is harder to do.
Yes I agree that europa leauge looks harder but their opponents is much harder than them, so they must prepare their very best to win for the game for next match. Well I see them shaking also their feet against the actual situations of the game match, but they remain brave enough to face the actual scenario.