Hyena wrote:My opinion on this is that he is trying so hard to get back into his father's good graces that he took the city that not only defeated his father (and killed his brothers), but that held him "captive" for nine years (ignoring the fact that while "captive " he was treated like a son and allowed to bang Roz for free). He's trying to be ruthless when it's not in his nature, so he comes across as bumbling and incompetent. And I think he also wants Winterfell as his own, seeing as it's history and importance in the realms is legendary (its founders were part of the First Men on the continent, if I am understanding it correctly).
That's pretty much it. If he's Lord of Winterfell, holding one of the most powerful castles in Westeros, the seat of House Starks and an ancient line of Kings in the North, it pretty much wipes his slate of embarrassments clean. Being a ward of house stark, being "given away" by his father, being mocked by his sister, being derided by his own men - all of his real and perceived slights are purged. And it wouldn't really take much - the castle's so easy to defend (thanks to very high double-walls, among other things) and the lack of a serious army to take it away means that if his sister just gave him a few dozen Ironborn (men which Theon feels should rightfully be his anyway, since he's the son and he was the one with the bold plan to capture Winterfell in the first place), he could truly redeem himself.