Here's how I'd rank WBW, going by how the fighters do against others in the division in general:
1. Nunes (I think she has the power and striking to hurt Holm and has a takedown threat and ground game too)
2. Holm (she beats Miesha most of the time, but as a counter striker, has a tendency to only edge certain fights)
3. Rousey (obviously does badly against Holm but is generally a destroyer)
4. Tate (well rounded and has heart but not good enough in any one area to consistently beat the top women)
5. Shevchenko (I admit I don't know much about her but she fared well against Nunes, she's well rounded, and has supposedly beaten Joanna in MT)
there's also Germaine de Randamie, Julianna Pena, Cat Zingano.
I genuinely think Amanda is the best WBW. This isn't just the recency of her fight talking.