Let me state first off that this is in no way a complaint. I love Bethesda, Skyrim, and Bethesda will be getting my money day one for Dawnguard.

I also recognize that I do not know much about Dawnguard, and my opinion is based on not much actual info.

The way I see Dawnguard so far, is that it adds a "main" type questline with new armor and weapons and enemies onto the land we already explore. So did KotN.

What I want is Shivering Isles. A completely NEW area unlike anything we have to explore.

Do you guys thin such a thing is coming?

EDIT: I guess what I am saying is that when I think of Oblivion, the only thing that really stands out for me is the Shivering Isles. I hope we get something similar. But even if we don't, Skyrim is my favorite game of all time.

I was under the impression that dawnguard would be in a different realm, like the shivering isles.

It will be, partly.

No. There is a small area called the Coul Cairn, but it isn;t very big. Maybe the size of Blackreach.

We are getting a new areas that we have never seen before. And we might have the power to block out the sun perminatly which is interesting when you think about it...

The area isn;t very big - certainly not anywhere near the size of The Shivering Isles.

According to one of the Dawnguard interviews, there is another area added. Aside from the Soul Cairn, I don't remember which video, but it was brought up in relation to questions about Falmer I believe.

Nice! I hadn't heard that. I am excited.

So you've been there already?..Tell me how it was.

It was pretty cool, actually. I wish it was bigger.

I read the same. I'm assuming that they will not feel like shivering isles however since they are smaller seperate areas. I think it will feel more like skyrim itself has been expanded.

Yeah, given the Frost Giant in the trailer I have my fingers crossed for Solstheim, or part of Solstheim.
Trying not to be too optimistic though.

I honestly, I don't have a problem with that. I love Shivering Isles more than anything else about Oblivion, I've made more than a few characters who head straight there, & pretend the core game doesn't exist, but not being a distinct area isn't gonna upset me, seamless transitions work. I like it well enough in Bloodmoon. Though hopefully it won't be such a long swim, if that's the case.

This is NOT an expansion. It's highly unreasonable to expect expansion-sized content from an add-on like Dawnguard.
To answer you're question: Dawnguard is somewhere between KoTN and SI.

My only complaint is that I read if you join the vampires you get your own castle to upgrade but if you join the Dawnguard you get to just live in their fort. That is pretty much an uber ripoff for nonvampires.