All of my classics' books are packed away but I agree that she should have more power especially since becoming a Hunter. Have you poked around on theoi.com, they have great resources on what sources say about various gods in stories?

I like what Riordan did but I stopped reading after Lost Hero as the addition of the Romans felt awkward to me. I'm glad Thalia isn't fully going away as I find her fascinating and she and William didn't get enough adventures, they need to have some.