I leveled my DK (Rash) to 80 as my 3rd toon to get there. I had it as a farming mule. Herb/Mine. When I got it there I wanted to get decent enough gear during wrath's waning times so that he's got decent gear for leveling up in. I then realized I hated the rune system and didn't enjoy playing it. DK done.
Yesterday I sat down to level my priest as shadow. For some reason I just wasn't enjoying questing and decided I'd try tanking an instance on my DK. I have to admit, as much as I'm upset about it- I enjoy it! I ended up 2% away from 82 and a whole ton more tank gear on Rashlen. I'm thinking this may be my second 85 and it really isn't all that bad in that it's a dual farmer and will help provide some much needed gold (I've burned through ~20k so far since Cata's ship) and I've been altogether too lazy to develop a new market in the AH yet.
Patch 7.3.5 Tomorrow
3 days ago