The Marks get harder more into the game. Believe me, to me this is the most challenging FF I have played, but I guess that this is not the case for everyone. It does not have the most challenging enemies though.
About paradigms taking too long to change, try to do what I do. I change the paradigms after I send Lightning to attack an oponnent which is in the air or that has been sent flying. After she finishes her combos in mid-air, change the paradigms before she returns to the floor. There will be no videos for the paradigm shift and adds some more challenge and dynamism to the battle. :)
This game with the 12th one has my favorite battle system.
Nintendo is selling their IPs to Microsoft and this is true because:
http://gamrconnect.vgchartz.com/thread.php?id=221391&page=1
