Heroes like Hanzo/Widow attract the worst type of teammates in FPS. This is true across any FPS that allows you to be a sniper class. I put a lot of the blame on Blizzard, when you design such a teamwork heavy game with only 6 spots per team, putting in heroes that are largely worthless when played by 99% of the player base is just bad design to me, especially when you know they'll be popular in spite of the fact people suck with them.
Ana is a well designed sniper, she fills a role that most of those types of players won't touch because they have no interest in actually helping the team, lol.