True. What always got me about those complaints is that they ignored the same aspects about Luke. I mean, the kid flew T-16's on Tatooine and had no formal training, but he's given the keys to a shiny new X-Wing and on his first actual space flight (which was also his first military engagement) just happens to be helped by the Force so well he single handedly blows up the Empire's most potent weapon and heavily guarded secret with one shot while more experienced pilots die all around him. Then he spends, what, a week? With Yoda and is able to handle himself against Vader in Bespin after never really even sparring with someone with the weapon or getting training in any of the forms of lightsaber combat.
Just saying.....Rey might be a Mary Sue, but lord knows, she isn't the first.