People who say the Kusts are fail are idiots. Seriously.
You're a heavy cruiser, not a Battleship. Of course you're not going to have range to fight on the battle line.Yes, primary focus is AA, but if there's a cruiser, destroyer, or frigate and the battleships on your team are busy with other more important vessels, it's your job as an CA to kill it.
Having the Kust Ls also does give you BB2 range. There's been more than a few times that I've stepped up in my moltke and provided both a distraction as well as just a little bit more firepower by charging and making my gun flashes draw fire.
If you're worth anything, your AA guns (which should only be the Lv 55 4.1"/65 SK C/33 As) insta jib the scout or two, then you take advantage of the dark to smash other AA ships if you can. Or land AP on that Lion 2 over there.
Moltke, properly fitted, is the best escort CA out there. If you only put AA on, you're worthless to the team later in the game. If you only put HH and AA, you're worthless late game more often than not. If you have a scout, your 11" Ls, AA, and good battle sense, you are a amazing credit to the team for what class of vessel you are.