Interesting comparison with Japan, Georgiy.
Russia has always been very much it's own country, and distinct from the rest of Europe. This is, however, in recent times, largely due to the Communism/Capitalism divide. If we're hypthothesising, as I am, about a Russia post 1918 with the Romanovs in rule, however, I'd see Russia as becoming much closer to the rest of Europe. Industrialisation was beginning to take a hold, democracy was starting to be asked for, there was a much wider access to education, etc. Personally, I think that if the Romanovs had retained power they would have done so as a much reduced, constitutional monarchy with very little say in politics. This would bring them much closer to the British monarchy and other European monarchies of the time, and with the role of Tsar/Tsarina much less about ruling the country than before, I think changing the law of accession would have been a much less problematic issue and something Nicholas would have been far more likely to consider, especially if Alexei, as one would suspect, had become much weaker as he progressed towards adulthood.
The new bourgeoisie were very influenced by Western Europe, so those in power would have been too. Women's rights in the rest of Europe may have led to Nicholas being forced to change the law of accession by his hypothetical parliament.
I don't think Alexei would ever have become Tsar myself. If there HAD been no revolution, I think Nicholas would easily have outlived his son.
Rachel
xx