long time no see...
Here's my take of the O-class battlecruiser design:
The three planned ships ("O", "P", "Q") were intended to be fast convoy raiders capable of fighting against enemy CLs and CAs and able to outrun Battleships.
Plans for a mixed turbine-diesel propulsion and heavy calibre guns made the design grow in size. If built, the ships would have been some 15 metres longer than Bismarck, while only beeing armored against 20cm guns.
In my opinion a terrible and not very good looking design. Their supposed nickname "ohne Panzer Quatsch" (no armor nonsense) was very fitting, indeed...