How was Arsenal's season great? Coming second again for the 3rd consecutive season isn't supposed to be great for a team that's supposed to win the title at least once in those three years that they claim they had a great season. Anything short of winning a title isn't supposed to be considered great. After eliminating Real Madrid both the team and fans all thought they've arrived and thus winning the champions league was their agenda, lol.
Well, for a Premier League team, where it's considered, even though it's the strongest league and the highest level, it's not bad. Arsenal's bad thing is their lack of consistency , The fact that they beat Madrid in the UCL was when they used up all their gas From then on, they lost everything, something similar to what happened to Inter when they eliminated Barcelona. That's as far as they went.
Arsenal can always shine when they manage to win more often;otherwise, they'll remain second-place.