How similar is Snyder's current Owl run to Morrison's R.I.P.?
I'm honestly not seeing it. Sure, both books host "secret societies" as villains - but they are not too similar, beyond that categorization. Their motives, back stories, characters, actions and plans are all very different. Is no future Batman writer able to use secret societies, because Morrison did?
The stories have a VERY different feel to me. I think those comparing the stories missed what Morrison was shooting for - and I don't mean that as an insult to Snyder. Morrison's took us much deeper inside the mind of Bruce Wayne; the fact that the enemy was a secret collection of villains and a - for a long time - unnamed evil is secondary to what took place in the mind of Bruce Wayne.
Snyder's story is much different, as the story takes place in a completely different setting: Gotham City; outside of Bruce Wayne, who acts as a hero alone, as opposed to the setting. This story is about the Court of Owls and eventually and potentially Thomas Wayne Jr. R.I.P. was a study of Bruce Wayne's entire life, to that point, and deeper than just that, even: what makes him, what could break him, and why.
I stole this, and can't remember where I read it, but: The Court is a "rip off" of The Black Glove, only as Batman is a rip off of Superman. That is to say, they are very different and unique to the other, despite both fitting under the same categories (caped heroes, secret societies).
Anyone suggesting the stories are the same, is missing a lot of what each writer intended and executed, in my opinion, especially Morrison.