It must be extremely irritating to have someone move into a nice neighborhood full of conventionally sized homes, and then poke everyone in the eye with a hideous McMansion. Fortunately or unfortunately, however, we live in America. We have a right to do what we want with our property, as long as it's legal.
And that's really the problem with most of these McMansion disputes in Utah: Planning and zoning ordinances allow them. We can't regulate bad judgment. We can't make people be good or considerate neighbors. All we can do is talk to our planning commissions and city councils about setbacks and restrictions before Mr. and Ms. Moneybags move in. It's the annoying but American way.