On ally side Dark Iron Dwarves and Void Elves look awesome (imo, male for DiD and female for VE) and make awesome runners for legacy dungeons with the speed boost (DiD hunter) and the pushback thing in theory is best for VE (so VE caster)

On horde side the Maghtar orcs just look awesome

I would go for having 120 of all classes if you can do it, as indeed thing may change re viability of which comp; or rather things WILL change, it's a given