Normal Mode this expansion feels closer to LFR then it did in previous ones. I go into a Normal Pug expecting to 1 shot everything. Not sure if that's a good thing or bad.
It's more dangerous then LFR (though I haven't done LFR since MoP) but I'm not sure if it's challenging enough to spark an interest in raiding for more casual players, since most pugs can just roll it.
What keeps me playing is the ever persistent progression of WoW. I like seeing my ilvl grow, and I like seeing my DPS increase or Durability if tanking, while talking up a big game with my friends.
I will say killing Heroic Gul'dan in a pug was very satisfying for since it took me a number of attempts. It was satisfying taking down Heroic Helya in a pug pre-nerf also. The way you progress in learning the in's and out's of encounters and thus start using your abilities optimally and perhaps even assisting the raid leader with call outs, or raid leading yourself. etc.