Shadow priest felt terrible to level 100-110 as even when mindsear existed and did tickle amounts of damage. I just leveled my priest as disc. I main boomy and I leveled as feral because I tried boomy on beta and it was a pain, just like I leveled my elemental shaman as enhancement and still had to play it for WQs initially because ele damage and survival was so bad. It's done in a few hours anyway, I don't see why it's such a huge issue, although it would be nice if there was a talent on 15 or something that made leveling/WQ less painful for specs such as these.