I think I have flown enough airlines of enough alliances to place my verdict:
- if I fly inside Germany (Eco), AB is slightly better than LH.
- if I fly short distance within Europe, AB is slightly better than LH (which is better than AF/KL).
- if I fly medium distance within Europe, AB is equal to LH.
- if I fly long distance in business, AB is far back in service and seating.

The problem with onboard warm food for business can be tackled easily, since it is already on board for additional payment.
The problem with business seating in Europe can be solved easily, as also ther airlines offer economy seating with a blocked middle seat.
The problem with missing lounges can easily be solves, since DUS and TXL (over gate 1) already have them.
An alliance, that can bear Iberia, can also bear Air Berlin.
What it get's in return is a tight network in Central Europe (the first time LH could not prevent this from happening, although it has cost AB all profits).
I am just wondering how the Palma-Hub (dislike the airport and the touristic clientel, but have lots of flights to Portugal and Spain on business via there) will suit IB.
After screwing up on LX this is the best option OW has in Central Europe. Since AB was trying for years to surpass LH in service, I always hoped they would go to OW, but it was more hope than based on reality.
As one of the few frequent BA customers from Germany I am glad the "better-than-average" have found together and LH inflight for me is average.