To be fair back in the day climbing on pockets was very specialist. Especially in the Frankenjura where the locals were the best at this style vs now when visiting wads generally take down any thing anywhere. Pockets at climbing walls were totally non existent, campussing didn't really exist and hence it was very hard to train for them. So I can see why Ben would have thought AD was harder at the time. Ironically the Frankenjura is now considered relatively standard in terms of grades and reguallry gets beaten my visitors and locals alike. Ironically Hubble is probably even more specialist, being a route where you don't really pull you just hang a series of horrendous positions. Can't think of anything else like it bouldering or routes in the many places I've visited.
AD only has 1 mono certain ascentionists just decided to use 1 finger in some pockets. But essentially these days it's way easier to train for on pockets on the board and campussing. Without building a vague model of Hubble it's really v.difficult to train for and they sure don't make wall holds like that. Probably why it has repulsed so many people climbing that grade or harder.
So as for skipping 8c+, maybe it was an Usain Bolt moment where teh current record is smashed rather than just being beaten. Given Graham/Ondra et al have downgarded so many of the overgraded routes in tha past decade and upgraded others (often the old school ones) who are we to argue with an upgrade. And if it & AD are only 8c+ then maybe everything in the world need to be downgraded (let's face it this isn't going to happen).