I like your composition, the framing works well here. It looks to me like you were trying to bump the colour up a bit in the sky by increasing the saturation, but it's a bit too high in the boats now, at least to my eye.
Venice has a lot of overcast and foggy weather, it's a problem for everyone. I was there this past fall and it was pretty rare to see a sunbeam, mostly dull, flat light.
I have recently posted a Blog entry on my website (
here) about a black & white image I took there, my approach to flat light in Venice.
Jay