I basically agree. A great deal depends upon whether the UK joins the war and, if so, what level of enthusiasm they bring to the party. If they stay out, a long war is not necessarily to the disadvantage of the CP. UK participation also affects Italy and the US.
One likely scenario would be - 1. a bloody stalemate in the West close to the existing border, 2. a few striking victories in the East adding up to earlier and larger Russian casualties, 3. CP occupation of Belgrade but stopping at that point, 3. Romania joining the CP. Then - maybe even as early as 1915 - an armistice with 1. status quo ante in the West, 2. the creation of Polish, Baltic, Finn and Ukraine buffer states in the East with German princes as monarchs, minor adjustments to the Ottoman/Russian frontier, 3. Russian reparations, and 4. the creation of a "Council of Europe" to try to head off future conflicts.
The kind of war we are discussing has a completely different effect on the populations of the UK and France - no rape of Belgium, no threat to Paris, no Edith Cavell, no Germans on the English Channel - just a frustrating and futile French offensive into Lorraine which bogs down with very heavy casualties. It will be much harder to incite the French population (and probably impossible to incite the British population) to a high level of enthusiasm for this endeavor. With governments that are popularly elected, the public's view of the war becomes very relevant. Sometime in late 1915 or early 1916, the sentiment to wrap things up and call it quits may become overwhelming.
The Russians will take more casualties and lose more land earlier and they will not have any significant successes in the balance. Because of the incompetence of their leadership they may blunder on but there may be some advisors to the Tsar who begin the perceive the danger of regime change. There may also be less of an appetite on the part of the French to continue to loan them money.
