Dungeons and Dragons is a gaming system that has existed for decades. D&D 4th edition was widely disliked by the old fan base. It was widely viewed as being overly simplistic. Sales fell a lot. A lot of the fans switched to Pathfinder which was like a slightly streamlined 3.5 edition game. Pathfinder made their core rules all available online for free. D&D's handlers took it as a wake up call and addressed their competitive issues. They went back to their roots and they recruited players to beta test their new edition and give them feedback. From people who have been playing D&D since practically it's inception, they view 5th edition as the best addition of D&D. On a unrelated note, Kings of War function as a slightly streamlined version of 8th edition and it's core rules are available for free online (in a few days when KoW Version 2 hits the internet).
Does this mean we will get the best version of WHF after a couple of years with AoS, because I can deal with that I haven't tried out Kings of War, but I'm getting more and more interested in the game system. I also just like looking at how different people comes up with rules for battling creatures moving around a battlefield, that's always fun.