One consideration is that at Michigan, I think you’d have to be more assertive to make sure that you can do things like have closer access to professors, get into all the classes you want, etc. My son was planning to apply to both for economics (didn’t end up applying to W&M only because he got in ED elsewhere) and of the schools he was applying to, he thought these two were the most different from each other (the largest vs. the one most like a LAC), and that at Mich he’d need to be more proactive.
There are many things to love about both schools and they’re both terrific options. Think about the benefits and the costs of both environments - large university with more resources but also more competition for those resources vs. smaller school; distance to a city (and which city) if that matters to you (Ann Arbor is an hour or less from Detroit, Williamsburg is 2 1/2 hours or more to DC).
Your question about whether W&M is more easily navigated and easier to change your major probably can’t be answered as a comparison unless someone has been to both schools or has students at both schools – rather, maybe post something on both boards asking about the ease of changing your major, and other questions you have about that school. You could post questions about econ/business in both boards. Ask about whether people have had issues getting into the classes they want or time with professors on the Mich board; ask whether there have been resources they wanted that weren’t available on the W&M board. Ask about average class size in econ/business. Also look at the course catalogs for both in econ/business. Then you can compare with more information in your hands.