Yeah, I've noticed that in the Sims more detailed houses are liked more. There are some houses in Barnacle Bay which have less detail on the exterior, but I don't find them dull or plain; most of the interiors aren't a problem for me either - some of the houses in Newquay and Padstow (the grey stone houses on the opposite side of the island, the art gallery and the library are likely based on Padstow) would look boring/plain to me both on the inside and outside the first time I saw them. But it's probably just how people in Cornwall like their houses. In fact, I wonder if people don't like the houses because they don't know what the houses in Cornwall look like.
Well later Sims 3 worlds are obviously more impressive (like Bridgeport), but I've always liked the simplicity, or at least the nature, of the earlier ones - Sunset Valley, Riverview and Barnacle Bay have always been my favorites. Maybe people say it's boring because they like more detailed worlds, e.g. Sunlit Tides, Midnight Hollow, Bridgeport etc.
The landscape sure is nice, and the island looks amazing at sunset and during fall and winter (though for some reason in my game it rains non-stop in Barnacle Bay, maybe that's another similarity with England
).
I actually also thought Barnacle Bay was a New England-type town, but the architecture of the buildings, the main beach, the cliffy coastline itself, and the flower patches surrounded by hedges on almost every lot - these all seemed more fitting for England.