[Baalz]

I think I made a pretty good case for a vamp queen in my MA Aby guide. I was rather proud of that, and it wasn't a matter of shoehorning her in just to say I did. What she brings to the party above and beyond a lich:

Blood access. Specifically she blood and death, with obvious access to vamp lords which give you a strong entry into both blood and death(!). Sure you can add blood to a lich, but a lich with blood 3 (for vamp lords) starts looking a lot less like the cost winner.

Flying. This is particularly nice on a nation with no easy way to forge winged boots, and doubly nice on an immortal who you want to be able to use without fear of losing your equipment.

Stealthy. This is doubly important for an immortal because it allows you to 1) push your dominion someplace before you attack it. 2) Hop over hostile dominion stuff to where your priests are pushing your dominion on the far side. Combined with flying it gives you huge strategic flexibility.

Life draining attack. This is specific to the build I was going with for MA Aby, but if you add fire to the vamp queen you pick up phoenix pyre. Soul vortex is a must of course, but the down side is you have to sit and take at least one round of melee attacks before it triggers. Not so with the life draining attack. You kill her, she explodes. She immediately flies in to attack again, regaining a large chunk of fatigue *on her attack*. Even if she keeps getting popped immediately by whatever she's fighting she can often just explode her way to victory.

So, yes, there is a niche use for the vamp queen.