If they decide to allow you to level above 81 I would like to see a ramp up in enemy difficulty, maybe enemies scaling above 50. Although if this happens illusion and conjuration needs to be altered. Master at lvl 81 is too easy.
I bothers me to no end that they let people get to that level. For this reason more than any other I wish they still had classes. I still play like I have classes because I have never played like my character is the master of all skills. My character might get three or four skills to 100, but never any more since I role-play that way. For example my Nord warrior using Heavy armor and a two handed ax is never going to feel the need to max out his Destruction skill (or any magic skill). Yet Bethesda makes achievements and creatures that you only get when you achieve levels by maxing nearly all your skills. I've never seen a role-playing game design that encouraged player to not role-play until I played Skyrim.