Originally Posted by
Tanaria
That was Kael'thas only.
No other Blood Mage has had those verdant spheres floating above their heads.
And if we really want to drill down into it, players were able to have fire verdant spheres over their heads, but they had to play as a Fire Mage.
Going back to Kael'thas - he mainly used Fireball and Pyroblast. In death, he also uses some Arcane spells as well as Fire spells.
So, having the spell "incinerate" or maybe "drain mana" does not take away that "blood mage" is like, 99% Mage based, what most people think as an extension to the Mages, which are core to Quel'Thalas.
Warlocks, as a main thing and what we know about them, just aren't a big thing within the Silvermoon and Quel'Thalas society, these days. It's on the same scale as the Stormwind Warlocks. They are there, but not used or do anything.