Gunners

No trips to eastern Europe, far southern Europe, or far northern Europe. Every trip is a comfortable distance.

In addition, none of the opponents is the "big club" or part of a dominant pair from their respective league. That's one of the challenges when you face an opponent like Galatasaray / Besiktas, Celtic / (Rangers), Olympiacos, Shakhtar Donetsk, Red Bull Salzburg, etc. They know they're going to win their domestic league, or at worst come in 2nd behind their one rival, so they push really hard in Europe since that's the only challenging competition they're in.

It's better when the opponent has a split focus between doing well in their domestic league and doing well in Europe. Sometimes when dominant clubs play in Europe they treat group stage games like finals, and go flying into reckless tackles, and so on. Clubs like Sevilla, PSV, Lens, and also Young Boys, Porto, Benfica, Antwerp, etc. have to also focus on their domestic leagues, so they can't have players giving 110% in mid-week if that leaves them shattered for the weekend games.

If Arsenal could have picked its opponents, these are exactly the kind I would have chosen. Not only avoiding the big guns of FCB and FCB, but also avoiding the teams that don't have to worry about their domestic leagues like Shakhtar Donetsk, Olympiacos, Besiktas / Galatasaray, etc.