Sure, maybe HTTYD isn't the best land in the park. But here's the thing: the majority of the kid-friendly rides, shows, and attractions will probably be in this land, as well as a lot of flat rides that any good theme park needs. This land will also be the closest thing we have to a natural land, as all the other sections of the park are built around cities, or, in Nintendo's case, a cartoon artstyle. Berk will have lots of rockwork, lots of water, lots of foilage. It'll probably be reminiscent of Pandora when all is said and done.
I'd go so far as to say that HTTYD is the second-most important land in the park.