Schlieffen Plan Reversed
I think it's at least theoretically possible that a few months before the war either Moltke (who had already tweaked the plan because he had serious concerns) or the Kaiser (worried about relations with his cousins, etc). Decides that, though they do need to take out an adversary quickly, it would be easier to take out Russia than France.
So, they flip the plan on it's head, send lots of divisions East, and just have a strong holding force (entrenched) near the French border. The Eastward mobilization might make Russia less supportive of Serbia. If not, when war starts:
1) German forces 3-4 times as strong in OTL annihilate Russian forces quickly, with some Austrian help.
2) France, unable (like Germany) to get Belgian permission to cross the frontier) either invades Belgium or must attack across a fairly narrow front. They do the latter and make gains, but are eventually stopped by the entrenched Germans.
3) With no one bothering Belgium and France not being attacked, England is slow to get involved.
4) Austria, not having significant issues against the Russians, more quickly defeats the Serbs and fares better against the Italians
5) The Turks, seeing Germany ready to annihilate the hated Russians, joins quickly and enthusiastically. They don't initially concentrate on British possessions, but push against the Caucuses and Crimea.
6) Russia, with all its forward field forces annihilated, Germans, Austrians, and Turks pressing, and short of allied success, sues for a quick peace, agreeing to some Austrian terms in the Balkans and surrendering some Polish territory to Germany. Germany and Austria agree because Germany has no wish to invaded deeper into Russia and Austria has seen the cracks in its system. Not having endured as long a war, Russia is better able to withstand the revolution that soon begins. The White-Red war is much longer and more even.
7) France, seeing slower progress than hoped, and with news of continual German victories against their Russian allies (meaning more troops likely headed West), sues for peace. They return to a status quo with Germany.
What do you think?