I got into the hobby about 2 years ago, starting with 40K. I liked the background of fantasy, but I literally came into it at the time age of sigmar began, and I was never really a fantasy guy to begin with, more of a sci-fi.
That said, I loved the lore, as Warhammer just has this special blend to make it engaging. I was, and still am in some regards, mixed about the Old World being gone (more because of the minis they axed, had they kept those, I probably wouldn't have minded as much). That said, I really enjoy the lore in AoS, it is absolutely undeveloped just as WHF was in its beginning, and any comparison to the glory of the WHF world will result in it being blown out in that regard. And yet, I find it great in its own right, and I think many would have had it not followed on WHFB and been its own thing. I think, while it never will occupy that same spot as WHFB did, it will grow into its own, and I think the GHB and especially the Kharadron overlords really began to sold people on both the game and the universe. I love 40K, but after playing AoS I realized it did something more important than any other game - the models played like the fluff entailed that they did.
When I place a vampire lord on the table (I play VC/Death), s/he fights like a vampire lord would. When I have a horde of skeletons to command, they fight, die, and return like the never ending hordes of mooks that they should be. I love the Old World, I bought old lorebooks, play TWW, etc to enjoy it, but I enjoy both in their own right. I'm always mixed on which universe I enjoy more, and I love some of the older models, and maybe AoS should have been 9E, but at least the universe lives on in many respects.
Age of Sigmar may be a mixed bag, but I think it has a lot of potential, and it paved the way for a better grim dark future - soon my Blood Angels will play like Blood Angels, not gimped marines, and orks? Roight and proppah they soon will be!