A. J. P. Taylor in his “The Struggle For Mastery In Europe 1848-1918” mentions several Russian war aims which their leaders broached from time to time during the war. I found the mention of Hanover very quixotic leading me to believe that Nicholas II, for the sake of his Danish mother, might also have insisted a defeated Germany cede Schleswig-Holstein in its entirety back to Denmark which would be in keeping with his “Mainz” remark below.
(Page 527): “The Russians fought to perserve the free passage of the Straits, on which their economic life depended”
(Page 532): The Russians were in a different case. Though they invaded east Prussia for the sake of their French allies, they had no serious ambitions against Germany herself; their concern was to destroy Germany’s link with the Near East, the Habsburg monarchy, and they would welcome any assistance for this purpose.”
(Page 536): “…Russia and France, too, wanted to turn their backs on Europe. Therefore all were committed to the destruction of Germany as a Great Power.”
(Page 538): “The Russians were hardest put to it to devise practical claims against Germany; in essence, they asked nothing from her except to be left alone while they destroyed Austria-Hungary. Any territory they took from Germany would be inhabited by Poles; and though they had promised on 14 August (1914) the revival of the Polish nation ‘free in its religion, its language, and its internal administration’, they were reluctant to put this promise into practice. Therefore they fell back on vague talk of ‘destroying German militarism’: Prussia must be dismembered and, as a sop to supposed English sentiment, Hanover must be restored.”
(Page 539-540): “The Russian military men, in occupation of Polish Galicia and much disliking it, urged that they had nothing to gain from defeating Germany; control of the Straits seemed to them the only prize worth fighting for.”
(Page 541): On 4 March (1915) he (Russian Foreign Minister Sazonov) formarly demanded of his two allies that the Straits and adjoining territory be included within the Russian empire.”
(Page 542): (On 5 March 1915) “Nicholas II said to Paleologue(France’s ambassador to Russia): ‘Take the left bank of the Rhine; take Mainz, go further if you like.’ “
(Page 543): “The Russians claimed a further reward for approving this agreement (the Franco-British Sykes-Picot agreement): they were allotted Armenia and Kurdistan (16 Sept 1916).”
(Page 545): “(Russia) Having estranged Bulgaria by keeping her out of Constantinople in 1913, he (Sazonov) now hoped to win her over by the offer of Macedonia, which was in Serbian hands; and the Serbs would have to be mollified by great gains on the Adriatic. More vaguely, Sazonov saw the shadow of a union between Italy, Hungary, and Rumania, which would threaten his own project of a Slav confederation in the Balkans…. (Page 546)”Still Sazonov would only compromise: he gave up the Croat part of Dalmatia (to Italy), but demanded southern Dalmatia for Serbia.”
(Page 556) Allied war aims presented to President Wilson on 10 January 1917: “The Entente therefore demanded ‘the liberation of the Italians, as also of the Slavs, Rumanians and Czechoslovaks from foreign domination and ‘the freeing of the populations subject to the bloody tyranny of the Turks’. They thus committed themselves to the dismemberment of the Habsburg and Ottoman empires.”
(Page 556-557): “France should receive the coal-mines of the Saar as well as Alsace-Lorraine; and the rest of the left bank of the Rhine should become ’an autonomous and neutralized state’, garrisoned by French troops. In return, Russia should be free ’to fix her western frontiers as she wished’. By this agreement of 14 February 1917 France made at last the sacrifice which Napoleon III had always refused and which the Third republic had hitherto evaded. She abandoned Poland to Russia for the sake of the Rhine frontier.”