I still need the following Heritage sets;
High Mountain Tauren
Zandalari Troll
Dark Iron Dwarf
Mag’har Orc
Classes I like most (and actually leveled to max before); Arcane Mage, MM/BM Hunter, Any Death Knight and Balance Druid.
I do love Warlock… I just never leveled one to max before.
I have a little random system I like to use for this sort of thing. A dice roll that determines class, race, gender, and spec for a new alt.
For you, the four rolls came out as…
Female Troll Disc Priest
There’s your next alt. Have fun!
Wait what?
I tried that once, got a Nelf Holy Priest out of it. Sadly, determination wasn’t that strong and she ‘died’ at 30.
I am the product of Legion’s free boost. 
Too bad. That’s your next alt. The dice have spoken! xD
DID DK Frost.
Blue eyes fire beard what’s not to love?
Ah, alright well then in that case my vote is for a DID warlock. It is the one race that I don’t get the green fire on and keep the red fire. Casters in plate is cool looking.
Others being:
Mag’har priest
Ztroll Paladin
HMTauren Monk
I wished there was blue fire for them as DK skin.
Yeah I was super tempted to make a DID Dk, frost with a fire beard is just something about it.
But I went with mechagnome because he is an undead cyborg and that tickles me just so.
I tend to like making odd race/class combos.
Blue fire for DK skins, green fire for warlocks.
Damn that’d be sick.
I need to photoshop this now, hold on.
Today is the day you should change all that!
Make a dark iron destruction warlock and laugh hysterically when you sling chaos bolts that one-shot your enemies.
I created a macro tied to chaos bolt so that my undead warlock cackles while casting the powerful spell.
You work quick. Those look awesome. xD
Makes me question why Blizz can’t easily add such options.
Ok, so Dark Iron Dwarves are already awesome I made more. XD
Aye.Their beards should have that option as a DK. 
I think we might see it later, Blizzard didn’t add any DK specific skins to the AR’s when they added in the new ones to my knowledge. Might just be something they decided to leave until the AR customization pass.
A wonderful choice I say. MG’s have powerful racials.
You gunna play a zug?
Well, I would say the Mag’har have the best looking heritage set and would make an excellent BM hunter or DK.
If I make zug, will you kill me? 
Highmountain Tauren Hunter, I just love there heritage armor so…