Kingdoms offer smaller campagins then vanilla:the americas, crusades. britannia, teutonic. If you dont like to have these kind of smaller campagins you can get stainless steel that gives you the whole map and the new factions.

You dont need to uninstall m2tw before installing kingdoms and it patches to 1.3 if you haven't already patched

I think Kingdoms is worth it whatever these securom whiners say