All I'll say about the rules is...interesting. I like how simple they are, and that will certainly help with getting into the game...but the lack of complexity and tactics kind of annoys me. It looks like it will work well for all levels of play, from small skirmishes to massed battles, but then one could have said the same for 40k by just looking at its rules, and not the various armies and units...
I think GW have hit the nail on the head here in creating an easily accessible game, with simple rules and a low entry point, and I feel that will help attract a lot of customers that might not have otherwise entered Fantasy, or the GW side of the hobby for that matter. And the similarity in aesthetics between Age of Sigmar and 40k will also help drag Sigmar players into 40k, and vice versa. The problems I see are: a) perhaps the rules are too simple, and b) they have alienated the entire current WHFB community. Those two things might hurt them, but otherwise I think this might be a great new game from them, though no proper successor to WHFB.