Janet
I don't think Alexandra can or should be solely blamed for the collapse of the Russian government - it was a lot more complicated than that. However, her reliance on Rasputin was immensely damaging, and she does seem to have brought out the worst in Nicholas as a ruler, not least by her insistence that everything must be kept unaltered for 'Baby'.
While she undoubtedly loved Alexei, I don't think her attitude towards him was at all constructive. For example, I've been gradually working my way through some of the older threads on the forum and found it very interesting to read in 'The Crisis at Spala' that, according to Spiridovitch Alexandra was dead against Alexei having orthopaedic treatment to straighten his leg, and Professor Wreden had to insist on it against opposition from both parents. While I can appreciate that a parent might well be reluctant to put her son through more pain and discomfort, I think any sensible parent would recognise that it was necessary on the basis that he would otherwise be left permanently lame. Nicholas obviously had a role in Alexei's upbringing, but, given that Alexandra was a much more forceful character, I can't help thinking that he tended to go along with her rather than the reverse.
I'm happy to accept (I haven't read the letters) that Alexandra was always telling Nicholas to correct Alexei's manners and not to let him run wild, but by the time Alexei was at Spala he was 11 and it was rather late for basic lessons in manners (don't know about you, but I was certainly getting the 'Don't put your knife in your mouth,' 'Don't put your elbows on the table' business by the time I was four!). There were obviously practical difficulties in relation to Alexei's education, but the impression I have is that nobody actually tried very hard to resolve them. As with Alexandra, there has been a pendulum swing with people writing about Alexei. We had Alexei the adorable little darling, then Alexei the budding saint (some of the tales about Alexei's compassion are rather like those in medieval hagiography!). Now we have Alexei the brat to end all brats! The truth, as usual, is somewhere in between. I think he was very spoilt, and babied by his family, particularly his mother, and being at Spala didn't really improve matters because he was made rather a pet of by some of the senior officers. Some of the time he was doubtless a very pleasant boy, especially when getting his own way and being the centre of attention, but at other times he was a horror (as all children are from time to time, the issue is how much). I'm interested to see from William Lee's article on Dimitri that in 1909 Dimitri was writing to his sister Marie Pavlovna at the time of the birth of her son Lennart, and saying that he hoped the boy did not turn out like Alexei!
As to the girls and marriage, to suggest that they would have been happily married to Russians were it not for Alexandra is putting it a bit strongly and, I think, rather more than Alixz implied. Yes, Nicholas and Alexandra could have started looking round for potential husbands for Olga rather earlier than they actually did, but there was no particular need for haste (Olga was at the young end of marriageable age), and it was perfectly reasonable for them to want her to marry someone she loved (after all, the example of Olga Alexandrovna and Peter Oldenburgsky may well have been in their heads). As to marrying a Russian, it is interesting that KR and Elizabeth Mavrikievna were against their daughter marrying Konstantin Bagration-Mukhransky. As far as I know, there was nothing dubious about his character, so the reason must have been that they hoped for a 'more suitable' match. Tatiana Konstantinovna was, of course, on the more distant fringes of the imperial family, not like Olga (though Irina Alexandrovna was allowed to marry Felix Yussupov, which doesn't quite fit my thesis). Was Bagration actually an ADC to KR at this time? According to 'A Lifelong Passion' he was an ADC later on, and falling in love with an ADC was not quite the thing (like falling in love with a lady in waiting). Also, we should bear in mind that any foreign prince very close in age to Olga was going to be a bit young for marriage in 1914. Someone will no doubt correct me if I'm mistaken, but I think that by this time it was unusual for a prince to marry under 21 (the Prince Consort in 1840 is the latest example I can think of) and 22 plus was more common. Carol of Romania was born on 13 October 1893 so rising 21 in summer 1914, but Olga wasn't interested. The future Duke of Windsor was 20, but he and Olga hadn't met since 1909. Would a meeting have been set up if war hadn't intervened? (it is interesting to speculate on whether Olga might have hit it off with the future George VI, a much more serious-minded and conscientious individual than his brother - perhaps they would have got on rather well).