Tsarism did fall to a democracy: while it obviously didn't work, what with the people starving and the front starting to fall to bits and everything, Russia's provisional constitution was among the most progressive and liberal in the world.
Have the Whites get very lucky and Russia may end up as a land of warlords like China. That's sort of a regime...
Kill Lenin and fix some other things up, and Russia probably ends as a Weimar Republic/pre-Fascist Italy type place: diverse parties, economically moribund, an influential and unhealthily political officer class. Land-owners and industrialists may or may not retain their own influence, depending on how left the republic leans. To add to the fun, it'll probably be a bit bigger than the USSR, and a loose federation. The Civil War, in such a scenario, will be a bit of skirmishing here and there
But to get a properly differant two-sided civil war, or a particularly functional non-Bolshevik regime, you'd need a PoD before 1916.
What would happen to the Tsarist regime if WW1 ended in an early win for the Entente is an interesting question indeed.