How does Arreola stack up with Wilder's other title defences?

Arreola is probably the worst fighter in the WBC top ten rankings(he's 9 ahead of Molina)

No. None of those three were very good or rated remotely near the top 10. They were all undeserving of a shot at any version of the heavyweight title and cherry picks. Arreola was worse than any of them at this point in time. He is a 35 year old washed up fatso without the will power to train and get in shape for the fight of his life. He was ranked 46th by boxrec and totally unranked by everyone else. It was just another cherry pick title defense in Wilder's back yard. Wilder talks big but look who he fights. Why not offer Ortiz a well deserved title shot?

Is he better than Duhaupas, Szpilka, Molina? Worst Arreola is a shot fighter who had what 2 or 3 weeks to train

I would say Arreola gets beat by all of them, all those guys are hungry for a big win while Arreola is on the way out which explains why each guy while somewhat lesser known did much better in their effort against Wilder. Duhaupus would jab the ish out of Arreola because he is about the same size as Wilder and Arreola can't really close distance quickly to negate a decent jab. Szpilka probably out works, out hustles and out boxes Arreola. Molina is not some tactical challenge but he is a hard puncher who comes to fight, probably fun but Molina to me would be the fresher more determined guy down the stretch.

Around the same. One could quibble that one is slightly better than the other but none are particularly convincing right now. I don't think they're quite as bad as people make them out to be either. The Areola fight doesn't bother me because it was keeping busy after Pov fell through. The next needs to be for real though.

clearly the worst. was on a terrible streak. ktfo, close decision agains bum, robbery win against kassi, and robbery win against Kauffman.