Did the Soviet Union at anytime consider annexing any of its satellite states into the USSR? I read that Todor Zhivkov, the leader of Communist Bulgaria, once called the nation the 16th republic of the USSR and made requests for Bulgaria to become part of it, and was wondering if there was any movement by these republics to become part of the Soviet Union. Additionally were there any people in the USSR advocating expansion, especially considering some places like Poland had been part of Russia prior to the Communist Revolution?
The official line of the Communist Party of Slovakia counted on joining the Soviet Union after the war. The idea was represented mainly by Gustáv Husák and Karol Šmidke however it was strongly opposed not only by the Czechoslovak exile government in London, but also by Gottwald's Moscow-based Communist Party of Czechoslovakia and by Comintern (at least by its president Georgi Dimitrov).
It is unthinkable that such position of Comintern would be any different from the position of the Soviet Union.
See Gustáv Husák za II.světové války/Gustáv Husák during the Second World War, pages 258 - 261 (in Czech)