I agree that attention would have to be paid to make it fit the map style as best as possible, but my basic point is that the ocean should be a little more colorful to get a more ejoyable game 'feel'.
[Edit] A quick example of the feel of the map -- if you blur your eyes slightly, the original map isn't as easy to pick out where the ocean is compared to the colorized one (which yeah, may be a little *too* blue). Also, in terms of gameplay experience, say you're exploring a new area and you just reveal a corner of the ocean. If it's the same color as every thing else, it doesn't really stick out at you, even if you notice it. But if it's colorized, you get more of a fundamental feel of 'hey, there's a new part of the map'. (Sorry if I'm explaining that poorly.)[/Edit]
I also kind of think of it as a map updated by magic.. how else would the blank, unexplored areas be darker than the explored areas, which are darker than the area currently in line-of-sight (which changes as you move around)? In that regard, perhaps there is a little more leeway about how the ocean sytle could be handled.
While I'm thinking about it.. it would be interesting to eventually see some subtle magic 'special effects' as the cloth draws more of itself as something new is being revealed. (Assuming the map actually is updated with magic.)