Hi all..long time visitor but never thought to post until now but I have to say I don't see why WB needs solo films to make a good justice league movie. It's preferable yes but it's not necessary. I saw the avengers with my mom, girlfriend, sister and a few friends from college. Of the group I was the only one who saw all the marvel movies before hand and a few of my friends had seen maybe one or two, mostly iron man. But that didn't impact their enjoyment of the avemgers they loved it regardless of what they saw before..because it was a good entertaining movie first and foremost.
That's what WB needs to do and concentrate on, making a good movie. Regardless if they do solo movies first or go straight to JL, get a writer and director that cares about the material and make a damn good movie. If the movie is a good, quality, fun movie people will go see it and enjoy it, solo movies or not. The average person doesn't care about solo movies if the movie is good and they've heard good things about it they will go see it. obviously as a hardcore fan I'd prefer solo movies first but is it necessary to make a good movie? No, absolutely not
Sorry for the long first post