>If not for it, Russia would be likely conquered the world by now.

Learn your history. It performed very poorly in the WW1. It was backwards culturally, economically, and actually not very rich in terms of land(most of it is tundra). Even in the best case scenario it wouldn't have been much more influential/stronger than the USSR, which was organized and industrialized through brutality and fear, undermined its foundation and eventually collapsed. Such brutal methods are inaccessible to democratic European countries which Russia was headed to become before the communist overthrow, and the gained efficiency and the lack of civil war losses would have probably only compensated it the Soviet level. At least initially. And democratic countries generally become less aggressive and imperialistic in the information age, so there would have been less to fear.

>Empire greatly shrunk in size.

Only temporarily. End results matter. The only sizable loss was Finland and a bit of Poland. If you consider the Warsaw pact countries, which were USSR's client states, the empire even increased its size after the WW2.