If Trotsky won, then all of Western Europe including the UK would be communist in 1921.
But this case differs from the above -- T v/s S was a winner take all
When Assad wins, he's still going to have to constantly watch his back PLUS, he now knows that the rest of the "Arab League" openly hates him, so he'll split that and tag-team with IRaq. That leaves him as one dictator who has to constantly focus on keeping his Sunnis down AND it makes for a constant antagonism between the Iran-Iraq-Syria axis v/s the SAudi-Qatar-Turkey-Pakistan team
Assad winning is better than the jihadis winning and is better than Assad in 2008 -- he's weaker and will remain so and will also be constantly fighting internally and with the other Arabs.
You are 100% correct on both Trotsky and Assad.