The SMS Blucher was the last armoured cruiser built by Germany, in response to the looming Invincible class which the assumed would have 6 or 8 x 9.2" guns. As a result she was a 16,000 ship with 12 newly developed 8.2" guns capable of 25 knots. However a week after Blucher was authorised the details of Invincible came to light, with 8 x 12" guns and 26kt speed; making Blucher a bit of an oddball, if not actually obsolete.
WI instead of her OTL design the designers went a different way?
The first way I'd suggest is to match the assumed threat of 6-8 x 9.2" guns with maybe 6 x 11" of the type used in Von Der Tann 18 months later, with the displacement, speed and armour staying the same. This would make a ship pretty competitive with how the Invincibles actually turned out, but different to Von Der Tann which as per German doctrine would fight with the battle line once the enemy was contacted.
The second way I'd suggest would be a German version of the 1915 Hawkins class 'heavy cruiser' which was 10,000 ton displacement, long range, 31 knot speed and 7 x 7.5" guns. This was to meet an RN requirement for trade protection, but became the basis for the Washington Treaty type 'Heavy Cruiser' built for virtually all major navies. Such a type would avoid the line of battle.
Thoughts?