Great, detailed post. I think situations exist today where vector icons can be a good solution; however, the promise of design once, deploy everywhere for artwork and UI that requires attention to every detail ... the rendering/display tech is not yet available at scale.

I think an orthogonal challenge is convincing cross-functional peers that visual execution and all of the design details have a huge affect on the user experience, the product, and therefore the business. In my experience, it's rarely a straight-forward or painless debate.