Lens flare in movies used to be something undesirable. You'd try to avoid it. You'd remove it in post. It was a bug. Then, like static being digitally added to music, it became a feature. When it didn't end up in things accidentally anymore, it was added back to lend realism. This cartoon planet? Totally a place with lens flare! This thing you are watching is real!
Imperfections are interesting, and if you get the details right with the imperfections, you can create a world that feels more authentic than a sanitized, perfect replica. (See Kamino and its perfect, unblemished buildings...its smooth, video-game feel. Contrast this with the crappy, scraped up, dirty spaceport of Mos Eisley.)
For a while, it recalled a gritty authenticity. Later, it meant you were watching a J.J. Abrams movie. Then, it signified a desire to trade on an authenticity that may or may not have been present. Now I think it has lost all meaning. It's just something you put into movies because people expect it, because that's just how things are done now.
It shouldn't be so surprising to me that movies are as susceptible to shifting signifiers are anything else, and most of the time I deal with lens flare by just getting annoyed and trying to figure out how, logistically, in whatever situation is being represented, so much lens flare could even occur.
Then I shake my fist at J.J. Abrams. I shake my fist at George Lucas too, just out of habit.
Later, I wonder why anyone would want to make a "Total Recall" movie that has nothing to do with Mars.