I wouldn't have said that was Whalerace's primary issue. The map is small, with bugger all height variation and the carts constantly ride side by side making gameplay repetitive; there's never any tactical choice between choosing to push your cart or block the enemy cart because you can do both simultaniously. Or easier yet, play sniper because you can't use the cart as cover and the sightlines are redonculous.
The water can be annoying sometimes, especially when an engineer sets up a sentry nest underwater because assaulting something underwater puts you at even more of a disadvantage. But in terms of unbalancing pyro's, yea, if you're that bothered about afterburn. But otherwise it's a non-issue. We're talking about a map that's largely underwater, not one that has a river running through the centre of it like plenty of existing maps do.