In other words, it’s quite historical. The Central Powers’ navies were, at best, coastal defense navies.
Germany was only barely a blue water navy due to Tsingtao in China and its accompanying cruiser squadron. So it could only project a very limited amount of power, and with Japan’s modern battle fleet entering the war, it was hopeless. The High Seas Fleet, even with its strength could only operate into the North and Baltic Sea with any efficacy; beyond this was out of the question. In other words, “Die Kolonien mussen in der Nordsee verteidigt werden!” Britain’s battle fleet has the Germans pretty much contained when it comes to surface action. Hence, subs are the only real way Germany (or any of the CPs for that matter) can challenge Allied seapower and hit the Allies in the pocketbook.
Austria’s navy really has but one function, as it did in real life, and that is to stop the Italians from landing uncontested along its Adriatic coast. During the war, other than U-boats, the Austrian battle fleet went no further than the Straits of Otranto (to attack the Otranto Barrage).
The Ottoman Navy was in an even worse predicament from years of neglect. The Black Sea straits, in combination with a system of coastal fortresses, were the focus of its navy. The addition of the Goeben and Breslau did give it some limited striking power, but this was going to hide anyhow in the face of any serious challenge by the Allies (Russian Black Sea dreadnoughts and French and British ships in the Med).
So this leaves the Allies with one of their major advantages: command of the seas. This was one of the reasons behind the Gallipoli landings; it took advantage of one of the Allied strengths, attack from the sea. From there, it was simply mismanaged. The attack really should have gone toward Alexandretta to cut the railway to Syria and Palestine. The German colonies, with OOB rules, are simply throwaways.
Unfortunately, I am finding the OOB rules are unsatisfactory, and I am spending a lot of time on creating my own version (powered by D12s). This way, you can bring out some of the real differences in quality between the combatant nations. So a German corps/infantry fights and defends better than a Russian corps.