@Devils Advocate: Sin Cara is on the Third Person under the mask. Four if you count the Dark Sin Cara. The new person who is Sin Cara, has done a fantastic job.
They need to do away with his mood lighting.
On to the topic at hand.
AJ, Eve and Aksana right now are the diva's division. Can't say that AJ, Eve don't wrestle they do. They aren't that bad either at it. The fact that Eve is a "Model" Diva and can do a respectable job in ring is impressive. If Kelly Kelly could have devoted the time that Eve has proved to be done, we wouldn't be talking about how shitty the Diva's are.
The signings will definitely help the division, but only if the WWE gives them the time to show it.
Your roster of girls who can actually wrestle isn't that small:
Sara Del Rey
Yes, some are in FCW/nXt, but the depth is there. The only girls who haven't proved themselves as wrestlers are:
If you give those who can the time, there will be, to use Austin Aries phrase, a "Wrestling Boom" in the Diva's Division. If they don't dedicate the time for storylines to propagate, it will never materialize.