For those who hate the easy option, but would rather avoid too much of a challenge.
Not quite the easiest, but not quite hard either. These classes are more middle of the road, with fewer restrictions or specialisations to bog you down. These come with a mixed range of level speeds and class competencies at level 60.
Warlock
"Watch! See the ground shatter before us! Watch as the energy flows! It will feed our armies..." Gul'Dan
The Warlock is a mix of the pets of the Hunter and the spellcasting of a Mage, just with a slightly more shadowy intent. The Warlock has famously been one of World of Warcraft's best classes, with them always being required for most aspects of the game due to their self-sustain via Drain Life and Healthstone, Soulstone and Ritual of Summoning.
Pets are good for solo content
Can summon party memebers
Good utility
Free mount
Good crowd control with fear
Less damage than mages
Soul Shard farming
Threat managment
Life-tapping will annoy your healer
The class also has a variety of pets to choose from — the Imp, Voidwalker, Succubus and Felhunter. All of these spells use a unique Warlock item called a Soul Shard, which you gain from using Drain Soul on an enemy. They are also one of two classes to get a unique mount at levels 40 and 60, with the latter being part of a long and expensive quest chain.
Warrior
"I was away for too long. My absence cost us the lives of some of our greatest heroes. Trash like you and this evil witch were allowed to roam free, unchecked." - King Varian
The Warrior is the standard, reliable tank. Don't think that you can't DPS, however, as the Warrior can more than hold its own as a DPS. When paired with a healer in PvP, the Warrior especially takes on the role of an unstoppable plate-wearing badass.
Best tank
Amazing at both PvP & PvE
Hard to kill
Charge
Amazing in PvP with a healer
Will often be asked to tank
Very gear-dependent
Slow and hard levelling, will require food
Easy to outscale your weapon
Requires a healer to be good in PvP
From being the true tank class in Classic to dealing amazing PvP damage, the Warrior is one of the most popular classes. While their levelling is slow and very reliant on food, you'll be very popular at level 60. Just make sure you bring your shield and get into Defensive Stance.
Priest
"This one is old, but still not one of the first. These creatures were too hungry for magic to obey our masters, though they still prove useful from time to time." - Xal'atath, Blade of the Black Empire
The classic World of Warcraft Priest really does fall into its namesake's archetype. Probably the game's best healer, raid invites and PvP groups won't be hard to come by. Whilst the Priest does have a good DPS spec with Shadow, it tends not to be as popular as many other specs, and is a far cry from what Shadow is right now on live World of Warcraft.
Best healer at level 60
Paired with a Warrior in PvP you'll be near-unstopable
While slow, levelling is fairly easy due to healing
Fear warding on Dwarf Priest is vital for raiding
Amazing raid utility
Basically forced to heal
Shadow not as viable as in live
Levelling can be slow, must drink a lot
Doing solo content as Holy
Priest really is a tale of two, from being arguably the best healer in the game across almost all content, with raid utility thanks to Power Word: Fortitude and healing numbers to match, to being a pretty middle-of-the-road DPS. While we're not saying you can't go Shadow, be prepared for a lot of competition for the spot. You might want to find a guild that has a Warlock or two, as the Shadow Priest debuff Darkness is very good.
