I did mine as enhancement until 53 when I felt like I had enough talents to make up for the terrible elemental gear itemization (I'll be damned if I wear cloth on shammies). I had zero issues, even with the 7-mob pulls in RFD, until I hit Theradras and Shade of Eranikus. Those two were nigh unkillable for me, so I cheesed them with 70 alts. :P I had pretty killer mana issues as elemental, though. I'm sure you can get away with going cloth for more castery stats but it makes you squishy.

Up to you. I found enhancement to be hella fun.