Don't see anything new here, unless I missed something. Gav does nicely talk about the idea behind the AoS, but really it's basically obvious stuff: fresh new setting they can do anything they want with, and that GW wanted to take the Space Marine archetype and transplant it to fantasy setting. Really, AoS isn't any more childish or friendly than WHF was. The difference is AoS is a high fantasy setting, while WHF was very low.

That said, I'm not sure they're going about recreating the aspects that make Space Marines so appealing in 40K well, or if you can even 'force' it by just transplanting it.