User blog comment:Maxwell Cohen/Ben 10's Continuity/@comment-3974711-20131005173356

Many did not like some of the concepts that Alien Force introduced or redefined.


 * Anodites- Gwen was never hinted to be part alien in the OS. In fact, the way Max talked about his wife, it seemed the writers wanted to imply she had passed away.


 * Magic- Apparently not a real thing, just an extension of Anodite powers. Though the show pretty much retconned itself again once Charmcaster showed up.


 * Kevin- Was never meant to have alien roots, but instead a mutant, like many other minor characters in the OS. And he was pretty sociopathic even without absorbing energy.


 * Plumbers- The Plumbers were never meant to be an intergalactic police force. They were meant to be a less- refined Men in Black organization.


 * Primus- The Omnitrix in the OS was pretty clear. It was a repository for alien DNA. Azmuth's speech in the AF episodes "War of the Worlds" confirms that. Then they contradicted themselves with the introduction of Primus.


 * Ben 10,000- Very much unlike his previous incarnation, and a lot more lame.


 * Forever Knights- being less of a group wanting to use alien technology to rule the world to an ancient group wanting to slay a dragon, and then actually to splintered groups all doing their own thing.


 * Vilgax- going from "so feared in the universe that nobody but robots and hardcore bounty hunters would work for him" to "beloved ruler of his planet with cheesy costume and combo platter of powers".


 * Null Void- There was no indication in the OS that it was meant as an organized prison created by the Galvan and used by the Plumbers. If they were the intergalactic group AF introduced them as, then Phil would have broken rules for doing what he did, and should have been arrested earlier. As such, it shows that the Null Void was not originally planned for this.

That can't be all, but that's all I remember. Anyway, they made for a horrific continuity if one thought about it hard enough, that contradict some things said earlier episodes. Not all, but there were some. Hence to simplify things, Omniverse is tasked with bringing it back to Man of Action's intentions (though OV does have its share of continuity problems, but that's not something I'm willing to look into).