nah - shouldn't be a problem
Just rename the folder and update the wordpress options page.
What will happen though is you'll be penalized by the search engines who will keep on searching for your stuff in the old directories. You'll have 404 errors out the whazoo unless you tell the search engines how to handle the change.
You do that by adding something like this to the .htaccess file:
RewriteRule ^olddir/(.*)$ http://new.com/newdir/$1 [R=301,L]
That will send a 301 error to the search engines telling them that the file has been moved. That will make your transition go a lot more smoothly.
Hope that helps!