I tend to think that a "greater" Soviet victory in WWII makes annexation of Eastern European countries more likely, at least the ones that used to be part of the Russian Empire. After the Soviets took over the Baltic States and formally annexed them, they refused to dis-engorge them until the breakup of the USSR.
Alternatively, even with a post May 1945 POD, The Soviets certainly could annex Romania, Poland and Bulgaria after WWII, the local communists were Russian stooges and would have signed off, and the locals were so utterly defeated they could have hardly resisted. The only thing that prevented it from happening is Stalin wanting to minimize his PR damage post-WWII. If the Allies get more aggressive about the division of Germany early on, he might be less concerned with that and just annex the one or more of those countries as a shot across the West's collective bows.