I almost didn't post this but then I noticed that I seem to have a penchant for preferring the second game in any given series and I'm laughing at myself for it
because that's where they polish up the mechanics of the first game, and introduce the really good ideas that struck them while they were working on it but they didn't have time for
Though in my perfectly unbiased opinion, Dishonored 2 may be the strongest in that particular franchise, but it's not by much. DH1 and DoTO are also both incredible
although DoTO has more in common with the Knife of Dunwall/Brigmore Witches DLCs that were released to supplement DH1 - it's not really beefy enough to be a standalone game