>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.

>And then USSR collapsed due to overexpansion and not enough manpower.

It collapsed due to demotivation of the population and the elites. North Korean regime for example did not collapse, regardless of the famines and even shittier economic situation. Gorbachov specifically had grandparents tortured and sent to Gulag, so he probably had gripes with the political system.

>Russia would have been much stronger and had much more manpower to colonize and russify conquered lands.

Debatable. Without the revolution it would have been much more pussified. The British Empire collapsed momentarily, due to the lack of desire to murder lots of people to keep it whole. That's what democracy and the information age does to cultures.

Even if we take your supposition for granted, it only means that revolutions weaken states, fuck shit up, and the revolutionaries lose power eventually. So it's inapplicable in cases you propose it to use. I assume you don't want to live in a shithole recovering from a civil war(that would eventually collapse), or probably in prison after the inevitable purge.