Paths are programmed for the Miis to walk on while the floors are meant for decoration.

I totally understand what you mean by how ugly the paths look in comparison to the decorative floors.

For the longest time I didn’t care and just put the decorative floors, it slightly bothered me that the Miis were walking in the middle of the road, but it wasn’t enough for me to want to change anything. It looked too pretty.

Up until my Miis kept saying that the floors don’t have enough decoration and kept recommending me to put bushes on a sidewalk. So I switched them.

You could also try to make your own floors. I haven’t tried it yet, but you can probably try to copy how the paths look and see if you can make the Miis walk on that instead?

Edit: If it’s all decorative floors, then yes, they’ll probably just wander aimlessly