it is nowhere near any of them at all. It is more aligned to Thief, Deus Ex, Dark Messiah or any first person game with a stealth element.
You should check out some of the gameplay videos to get a grip around the game and how it plays out.
The developers reeeeally loved Thief, Deus Ex, Arx Fatalis and such games, that's why Dishonored reminds us of those games ^^
They also however had everything from Bioshock to STALKER in mind, when they created the game
To the last question, I'll go ahead and say it's a mix between the two. Dishonored tries to give the player a world with alot of depth and a strong story to be told,
but also to give off a great gameplay, a gameplay where you just need more, you simply can't have enough.
And honestly that is what makes a great game for me, A strong story, hopefully provocative in the way that I HAVE to make a decision or have to have an opinion,
plus a smooth and strong gameplay with some great features or animations where you just feel the rush as you shoot someone or drive a blade through a man's chest.
well that's my two cents, hope it helped
