Arsenal is not the same Arsenal you used to know in last season. If you are following Arsenal up this season you are suppose to know who Arsenal is now. Arsenal are leading the in the premier league and still doing well in the Europa league. If they are to be in the Champions league they would have been among top teams .
Arsenal have a bigger chance of being in the Champions League next season, because if Arsenal can manage to be in a good position and win the Premier League, then Arsenal will immediately be in the Champions League next season, as well as if Arsenal manage to win the European League. this season, Arsenal can directly be in the Champions League next season.
I feel like even if they are not champions, it is nearly 100% certain that they will be in the top 4, which means that UCL door is wide open for them. Obviously they will not even finish 4th if you ask me, and probably not even third unless they suddenly start to suck, they will either be champions this year which would be entertaining to see, or they will be second behind City, that is the two possible outcomes if you ask me.
That means they need to get ready for UCL next year and it will not be easy, it will certainly be a tough year and I am guessing that they are going to have some hard time because UCL requires a lot of experience in that kind of tournament.