> So it would only count as a regime change if he stayed to get killed by an angry mob?
It doesn't count as "been overthrown". Also, there is no evidence that he would have been killed. He might go under a trial in a court though.
There is one important thing you don't mention: the "referendum" was held after occupation of Crimea Peninsula by Russian military. Specifically, the article you refer to says that Russian military occupied Crimea on February, 27 and the referendum was held on March, 16.
Therefore, parliament could not vote freely as its members were not protected from pressure by Russian military authorities. You cannot vote freely when surrounded by enemy soldiers. Also at that time the territory was controlled by Russia and the parliament had no real power anymore.
Also, I do not know if Ukranian law at that time allowed a region to declare independence. You cannot hold a referendum whose outcome would contradict the law. For example, you cannot hold such a referendum in Russia.
> You acting like that doesn't matter, so you can regurgitate "Russian annexation!"
Let's look at the definition of "annexation":
> Annexation in international law, is the forcible acquisition of one state's territory by another state and is generally held to be an illegal act.
Russian army has occupied the territory earlier that anything else happened. Therefore it is an annexation. There was no significant movement for independence of Crimea before occupation.
> it very casually denies the Crimean people, as represented by the state parliament, their own representation.
Do Crimean people or their Parliament now have a right to separate from Russia if they change their mind? They don't. Does it mean that Putin, as you say, "casually denies the Crimean people their own representation"?
I don't think there are many countries where a region has a right to declare an independence. There are things that you cannot change with a referendum.