I'm happy to join Pavlov in the firing line!
Alexandra's period of political power was a disaster. Obviously her actions were not the sole cause of the Revolution, but were certainly one of a number of major factors (of course, Nicholas was partly to blame for leaving her in charge).
I also agree with Pavlov that Alexandra was by no means a perfect parent. Machine gun nests will no doubt spring up in front of me when I say that I am not a parent myself, but to my mind a good parent needs to have some objectivity about their children and to be able to step back from them, particularly once they are teenagers. What is best for an individual child is not necessarily what their parents want for them (just to take a fairly mundane example, one of my current students spent a period unhappily studying dentistry because that was what her parents, both dentists, wanted, despite her having no interest whatever). Alexandra had no objectivity at all. Oh yes, she loved her children, obsessively so, but she isolated them from ordinary life, she over-protected Alexei to an extreme degree, and fell under the spell of a charlatan, for that, to me, is what Rasputin was. Pavlov makes the very good point that Alexei was in good health from the time of Rasputin's death up to the accident in Tobolsk 16 months later. He also spent several months in total at the Stavka, and was in good health for most of that time, in fact, apart from the nosebleed at the Stavka, he enjoyed the best health of his life from 1915 up to March 1918 (and the Tobolsk accident looks largely self-inflicted). Partly, of course, that was because he was getting older and less likely to have minor knocks, but he was still managing without Rasputin. I would be most interested to see how Alexandra's sister Irene dealt with having not one but two haemophiliac sons - I suspect very differently.