Liverpool and Byaern Munich may still be quite promising but Arsenal personally I still can't put more hope. Because well Arsenal is Arsenal, at least they have to prove first that they are EPL champions, after that they can pursue UCL. Realistic right? because Arsenal must be able to conquer the curse of the English League first. If it's not a curse, what is the correct name for them? hmmmm 
I agree with this very much, Liverpool and Bayern Munich looks very promising with the champions league but again I will not completely write Arsenal off, reason been that this was similar case with PSG only that PSG was consistently a domestic champion in their league but Arsenal is struggling with the Premier League and the champions league. The just concluded season, almost no one believed PSG was going to win the champions, Arsenal even had more potential at the beginning than PSG dis but at the end of the day, PSG surprised the world, same is very possible with Arsenal so let's watch out for them in the new season, they may be the next big surprise in the champions league, we never can tell.