Do you wonder why some might find your fear irrational, given that the federal "assault weapons" ban has already done what you fear "incorporation" would do? You act as if the individual states were free to ignore the restrictions on ugly rifles. That is simply not so.
Second, the Federal AWB, back when it existed (again, the ban WAS allowed to expire), was passed using the power of the Commerce Clause. Second amendment incorporation or non-incorporation has no effect on a Commerce Clause law.
Third, as such, the Federal AWB was valid, constitutional law that the states cannot ignore, incorporation or not.
My concern is that, under incorporation, Congress bans all handguns and the U.S. Supreme Court rules that handguns are not protected by the second amendment as militia-type weapons since the average soldier doesn't carry one. A lower federal circuit court has already ruled this way.
Or a future liberal U.S. Supreme Court rules that "bear" does not include concealed carry. Many case rulings there.
Or the U.S. Supreme Court rules that "keep" means "keep in a state armory".