moving or redirecting WP

Hello guys, I’ve been wondering for a couple of weeks and still don’t have a decision. I would ask you to help me in this – should I redirect my old WP to a new one, should I delete the old and move the new to the old or should I redirect the old to the new via htaccess?

Here is the scenario:
My old site is up and running on the root directory of my domain. I’ve made a lot of changes, incl. the permalinks, WP structure and design to a sub-directory. Now I’m ready to show my new version to the World, but I’m not sure how to do it properly. The easiest way is to delete the root, but is this the right decision?