I judge that she was a good mother, if a bit overprotective. She cared deeply for her children, and they were her life, and she allowed them to have their own life within reason. I think she was close to her family and was very maternal, and her children knew that they were loved, and not smothered. She found fulfillment in being a wife and mother, although she had the intelligence and character to be more. She was a Empress, but she didn't rule the country although she messed with politics later, and firmly believed in autocracy. She was a torn women, who had tribulations, many involving her son. But she never let up in her love for her family. Besides love, she had a real relationship with them and real interaction, as you can witness in photos.
She was very protective, but then they were royalty and were isolated any way. Even today this is true of royal children, and it was more then, when royalty were even more sacred and held remote from ordinary life. So OTMA were not really any diifferent than any fellow royals in this way. True, they were held a bit more apart from court life than most of their royal peers. And this was directly due to Alexandra, who feared the influence Court Life might have had on her children. This was legitmate enough, and coudn't have continued forever. She wasn't understood by the court, so how could she expect understanding for her daughters? And, OTMA were raised a certain way, and she didn't want this to change. Who can blame her? I think she gave them enough of a life, with the officers on the Standart, or with cousins of theirs and ladies in waiting. As well, I believe that the first World War hemmed them in, amd caused ordinary life to become very different, and so their options were even more limited. They were so young then.
So, Alexandra was a good mother, a loving mother, sometimes strict, but not one who harmed her children by isolating them. I believe everyone relates to the world in their way, and even the isolated physically can understand the world in their own way.Isolation does not always produce what people think it does, although it has the effect of making you fall back on your family more, as OTMA did.