Inner Fire is pretty great, and it does its job well. Usually. The big issue with the spell was that it had so many hooks and drawbacks. Short duration, limited charges, and able to be dispelled. That's about two hooks too many. I don't mind keeping the Charges around because the spell supplies a massive amount of armor (for a cloth class.) I'm okay with making a Priest be careful about keeping it up at all times in PvP. In PvE, the 10 minute duration is just a nuisance and in PvP some random melee will burn away the charges in less than its full duration anyway. It was just an annoyance all around and a very unnecessary hook.
Inner Fire probably should have been unable to be dispelled right from the point they did it for Mages and Warlocks, but better late than never. That Enhancement Shaman will just need to swing his weapons a little longer to get rid of your Inner Fire, instead of just spam Purge to shut you down. To me, this is a good thing. To the Shaman... perhaps not so good.