Yes, there's something you're missing. All the PS filters with the exception of Gaussian Blur. In fact, we're all missing those filters. <G> No, you're not overlooking the filter. It isn't there yet.
Bringing raw photos into PS iPad is something else we're all missing. I take it you're just looking at the features to see what might be there to use once we can do that? Currently, your PS/PSE workflow with CR is what you have. The edited raw saved as a PSD or TIFF can be brought into the iPad PS and further manipulated, primarily to build composites with it.