while i can understand motlke's desire to play a more complex character i've always found vicki's placidity a nice, and necessary, counterpoint to the over the top, scenery chewing characterizations that happen elsewhere on the series. she had a soothing onscreen presence and moltke's quiet, even rather flat, acting style and slightly aristocratic bearing gave a gravity and seriousness to some outrageous situations.
rather than complain about it all the time alexandra could have made the most of a prized position in the story. still, she was pregnant, and would have had to leave sooner or later anyways.
that said i've always thought, just for fun, a vain, glamorous and pleasure seeking victoria would have been fun for a few months in 1970 parallel time.