Yes we'll see the rest of Rohan, as well as Edoras etc, but the main feature will be Helms Deep.
I agree with the sentiment that the updates are getting fewer & fewer as the years go by and it's getting more & more expensive too, but that's mostly coming from Warner Brothers now.
I've played for over 6 years now & have 4 x Lv85's in the game, but find it increasingly hard to log in at all, until there's a decent update. Shame really, but they have a good F2P model, but seems little comes back in the way of content updates... they seem to save them now for the expensive Expacs.