Arsenal have managed to play consistently in the last two seasons. This shows that Arteta has succeeded in building a solid squad. Arsenal has a big chance to win the EPL next season. They seem to have been unlucky in the last two seasons. I'm not saying Arsenal are inconsistent because of the fact that they don't have much of a points difference from Manchester City. They were just unlucky when they got bad results in several important matches at the end of the season.
But I'm not sure about their chances in the Champions League. Arsenal is one of the best in England but in the UCL the competition becomes more difficult and there are many teams that have also improvised. Real Madrid and City are still the strongest candidates in the UCL next season. So far I see no other team that has the same level.
Arsenal had consistency performance in last two season but keep can't reach the higher round in Champion League after this season eliminating from quarter final round.
Arsenal performed well in domestic league keep pressure Manchester City until the last matchday before winning Premier League trophies in Champion League they can't performed well as consistency in domestic league.
Arsenal seems lack winning mentality on many crucial matches when facing top teams, I doubt next season their perform well in Champion League if the knock out round or quarter final round have to face top teams such as Bayern Munich or possibility have to face Real Madrid. Arteta need improving his teams with winning mentality against the top teams and Arsenal is the only of big four Premier League teams never winning Champion League trophy.
It has become commonplace for Arsenal to fail in their last 20 seasons in the Premier League. I no longer surprise them in domestic competitions, but to be honest many of us hope Arsenal can do better. In the Champions League Arsenal's struggles tend to end more quickly due to a lack of mentality, but if Arteta can stay longer then maybe he can help Arsenal win something big.
For next season, Arsenal have also confirmed that they will qualify for the Champions League. Arteta must be able to perform better than last season, but the hardest thing I can imagine is making Arsenal have a winning mentality. Indeed, Arsenal has many players with above average quality, but when it comes to mentality it is difficult to expect them to be successful.