Something I have pondered under the so-called East First scenario, an overall better war for both CPs in the East, getting to OTL 1917 line of advance earlier, a more defensive Russia holding basically Estonia, Belarus on the marshes and some jagged line across Ukraine. I cannot yet get myself talked into Nicholas pulling the plug but I can ponder a palace coup that crafts a sort of, kind of PG with as much legitimacy and illegitimacy. Obviously he Western Front looks vastly different and the USA is further away from becoming a belligerent too, so winter of 1916 is when the Russians fear the Anglo-French cannot win or will not save Russia, a separate peace.
Generally I find talking away the H-L dictatorship does more to solve German problems, the blockade is not s bad as their mismanagement and shortsightedness, with civilian administrators organizing the economy, a leakier blockade and saner approach to a peace feeler, things look far better. I will not say the CPs go straight to victory but they have a potent base to pivot from into 1917, strong enough to potentially cascade an armistice, something I think the H-L brain trust cannot accomplish but a saner General Staff and Kaiser who can be rehabilitated could settle for far before things in Berlin get dire. It takes changes to both Germany and Russia to settle out earlier, plus you need to take down the Entente ability to deliver on rebuilding Russia, i.e. no USA money looming large. Plausible but improbable.