Still, that's no more than a de facto
consort who acts as a regent now and then. Catherine of Aragon, a queen consort who also acted as regent for her husband, was more significant in government than Mary II, a queen who was actually a monarch - Catherine even defended England against the Scots!
Poor Mary II is remembered only as the wife of the King who overthrew James II & VII. The beggining of this thread indicates that there are people who don't even know that she was a monarch.
I wonder what would've happened if she accepted the parliament's offer to reign alone. Perhaps William would've abandoned her and her father would've had more chances to reclaim his throne. Perhaps Mary II was actually smart and not as submissive as we think - is it possible that she knew how fragile her reign would be without her husband's army? I know, so much perhapses :)