Can I just re-post what I put last time
Completey changes the world, I'd imagine Libya would get gobbled up by the British or French Empires eventualy.
No Ottoman collapse in the Balkans means that the states like Serbia who benefited from the war are far weaker and can get gobbled up in turn by the Hapsburgs (Who placed Imperialist ambitions that way after defeat in Italy and Germany), by that I mean creating protectorates and such in Serbia and Montenegro and sphere of influence on the rest of the Balkans. Russia as such doesn't create its Slavic alliances and as such don't come to blows with AH.
I'd imagine the great powers would come to blows eventualy however it would involve a stronger AH an Italy less willing to (and less capable of) being involved in a wider European war (Potential neutrality) Russia is weaker and the Ottomans are more powerful and more involved on the CP side. This combination has the potential for A CP victory TL and the inevitable Germany wank and Federalised A-H empire that follows.
As for specific event, as this war is more concentrated on Germany and Anglo-French rivalries I'd imagine it'd be a colonial incident (perhaps Morrocco). This TL doesn't nessisarily mean Russia is out as Germany saw 1916 as their last chance to take out the Romanovs before they became a superpower so maybe victory in the west and disaster in the East WW2 style, who knows?
Regards Bobbis