It looks like it has that combination of Paradox grand strat comfy-ness and crazy original narratives. There's no single thing about it that is super exciting, it's just a lot of good ideas and good stuff coming together to make a whole package that is appealing.
I betcha a lot of people will end up having complaints about the combat being too simple. I'm not the kind of player who likes to micromanage his armies on the battlefield in games like this, but even I can recognize that it looks like you just send big blobs of units at eachother and hope your outfitting + numbers beats their outfitting + numbers. I imagine people will complain bout it in the same way they complained about Endless Space's combat (which I really liked). Then again CK2 wasn't really a tactical warfare simulator either and everyone loves that so maybe not.
I think there's a lot of good reasons to be optimistic and excited that we've seen on streams and now some of these LP's. Shit looks pretty compelling.
[youtube]1sN6LQykAdM[/youtube]
Watch the Ikarzuri in the south.
Can you see what happens?