We have traveled all over the world on our own, so we are very comfortable in areas with major language barrier. We have only done one ABD (SoCal) and it was wonderful. Everything was taken care of. We did this one because at the time we went, it got us into Henson Studios and the ABD was the easiest way to get into Henson. It also had some other things that we could not do on our own, such as super early entry to
Disneyland (I think it was like 6:30a and we were the only ones in the Park).
Everything was top notch, food, hotels and service and it sure spoiled us. But to continue traveling the amount we do, we can't afford to just do ABD. We have another one booked, to Egypt. The reason we choose ABD is because we didn't want to deal with all the logistics of trying to do a similar trip on our own, additionally they have some exclusive access things.
The other top ABD's on our list which we have not booked are Greece and the Laos, Vietnam and Cambodia. Those have alot of hotel changes and one of the issues we have when traveling is it's a pain to tote around our luggage from place to place. Then arrive at our next city, go to hotel, have them stow bags while we head out. We don't have to worry about that with ABD.
I'm a planner and enjoy planning our trips almost as much as taking them. So the only negative I would say is it just felt weird as literally no planning for them. Other than deciding your airfare and if you are coming in a day in advance what you want to do. It wasn't actually a negative that'd ever deter us from booking, it was just a weird feeling I'd say with no planning needed.
Not familiar with the Germany itinerary so I looked it up. If you arrive early, I'd recommend checking out FC Bayern's stadium if you are into soccer, we did a stadium tour there and it was pretty cool. Another option is touring Dachau Concentration Camp. Lastly, I'm not sure where your welcome dinner is that's at a Bavarian restaurant, but Hofbrauhaus is pretty iconic, even if you aren't a big drink (we aren't) it's pretty cool.