Currently you can't get warden/ww gear from either drops or from crafting. My question is: Is this because the Devs don't want it as a combination of skills? Or simply an oversight/bug and the two skills are intended to work together?

The only way to run WW as an animal form is as a Butterfly. Butterfly has no skill set of it's own and counts as an animal form so 'no hands', and limited options compared to non-animals.

I'd like to do a build with Warden/WW, but if it's never going to get gear, it would be nice to know.

Frankly, I'm not sure why WW was restricted to just Butterfly. Its just one more restriction on playing animal forms. And think of the poor pigs, waiting for Charged Pig to become a thing.