Actually the most realistic outcome. It has been discussed ad nauseum on AH.com, but with Britain controlling the seas Germany cannot challenge the Royal Navy. In that same vein, they cannot impose any changes of colonial territory, and if they do, they cannot make the British respect those changes.
Especially with the Belgian Congo, which was, of course, the cornerstone of Mittelafrika. To really get peace with Britain, Germany would have to vacate Belgium and respect its territorial integrity (including the Congo) entirely, since that was Britain's casus belli for entering the war. Only by doing that will Britain really withdraw and accept peace, since, to the British, it still looks like a victory. "We went in to defend plucky little Belgium, and by George we did it!"
Besides which, all of Germany's colonies were occupied by late 1914. Only a single band of raiders still caused trouble in Tanganyika, but not enough to suggest the territory wasn't lost to the Germans. So not only has Germany lost any chance of extorting territory out of Belgium (and by and large France), but they've also lost the territory they already had and have no way of getting it back.
So no Mittelafrika. Frankly, Mitteleuropa was more important to the German leadership anyway.
I was joking; I completely agree with you there. Nice map by the way.