I should be more specific: why is this hard for me? Because for lots of people, leveling a hunter is the easiest thing in the world, to hear them tell it. It's a super easy class that has high DPS and a tanking pet to keep it alive. I should be blowing through the levels.
Instead, I've just recently managed to get my draenei hunter, who I created back when TBC launched, to level twenty eight. In the time since I've created this character I leveled my original warrior to 70, created a new draenei warrior and leveled him to 70, and leveled a draenei shaman to 70, plus went back and leveled two horde (warrior and shaman) to 70 and created a BE paladin and got him to 65. I leveled a paladin to 65 faster than I could level a hunter to 28! What is this, bizarro world? My orc and night elf warriors both hit 70 and I created them more or less as alts to play with RL friends on different servers, which means they get played once a month at most, and yet, here is my hunter, a year into the expansion (over a year, in fact) and I am just now heading into the 30's. And to be honest the only reason I even cared enough to level him this much was because I wanted to get him a mount.