Are any of them really "Difficult" to level?
Only difficulty come in making sure you have enough Water/Food to deal with the downtime.
I leveled my priest as Holy, at no point did i think it was hard, it was just slow.

Must be a slow topic week....

surely the question should be, which talent build is the hardest / slowest to level. a non BM hunter, non demon lock, or non shadow priest would have as much of a hard time levelling as a protection warrior, i suspect.

I have had experience with many classes, and it depends on the level range. When it got towards the longer levels 50+, I had the easiest time leveling my feral druid to be honest.

At low levels, there isn't much difference. Paladins are the worst. Go retribution and everyone mocks you. Go holy and take 3 hours to kill a critter.

a non demon lock would have a hard time? the utter lack of downtime for an affliction lock made my leveling incredibly fast

U forgot druids... i can level up a druid much faster than a mage. Fight in cat/bear form, go back on humanoid form and uve got ur mana regenerated, innervate if need. Also u can travel around fast with feral swiftness, travel form and flight form when u reach lvl 68. Druids have high survivability, we can stealth, got lots of HoT, and we can easly run.
(+its a funny class^^)
REROLL DRUID!

U forgot druids... i can level up a druid much faster than a mage. Fight in cat/bear form, go back on humanoid form and uve got ur mana regenerated, innervate if need. Also u can travel around fast with feral swiftness, travel form and flight form when u reach lvl 68. Druids have high survivability, we can stealth, got lots of HoT, and we can easly run.
(+its a funny class^^)
REROLL DRUID!