Is there a balance Issue?

Since I didn't find anything about that, I thought this is the right place for that topic.
I don't remember WotLk that well, but I don't remember spell casting NPCs to be so incredibly strong!
Just wanted to ask if this is a known issue or common for WotLk, as this seems to be kinda unbalanced (I can easily fight against 3-4 Melee Mobs, but 1 single Spellcaster is already causing a problem)
Also I'm not talking about the Defias Pillagers only, but Spell casting NPCs in general.

Approach combat against casters differently and you will find it easy. Don't let them cast.

Some mobs can be strong in that way. Use line of sight to your advantage against them.

Yeah, just los them or kick them. They also usually die much faster then normal mobs.