I think it is unfair to place too much blame on Alexandra's shoulders. I mean, Nicholas was their father; didn't he have a say? He should have spoken up! Yeah, I know, everyone says he always gave in to what Alexandra wanted, but that's beside the point. He was their father. But the blame is always directed at her.
I suspect that, while the children were isolated because of who they were, a lot of this stuff about being deprived was exaggerated by people who blamed Alexandra for the fall of the monarchy, revolution, etc. They wrote lots of negative things about her after the revolution including that she was a bad mother who made her children unhappy. Let's compare her to Xenia, who allowed her only daughter, 18 at the time, to marry a sleazy guy like Felix Youssopov. Alexandra would never have allowed that and she told Xenia so before the marriage took place.
In any case, despite the attacks, the prevailing view has long been that N and A were good parents to their children. I don't think that view will change much in the future because, I suspect, it's correct.