Hi ,
I’m excited about development of Paper2D in UE 4 and wanted to offer a feature idea, that may not have been considered already. I believe it would be really useful to be able to import SVG assets from Illustrator or other vector drawing apps into UE4 and then dynamically rasterized into a sprite context when needed. In other words, SVG file remains an asset in a UE4 project, and only rasterized once when it is used on screen, or updated when a sprite is scaled to a larger size on screen or when multiple resolutions of sprite are required. From my understanding, sprites are usually more performant in games, but vector graphics can take up far less storage space especially when high or multi resolution images are required, not to mention creation of sprite sheets/atlases. And of course, sometimes style of your assets require a more clean vector graphics look anyways. Seems like a waste to have to rasterize vector graphics into PNG files beforehand just to get that look.
I believe Vector/Sprite hybrid concept would make a lot of sense for Paper2d in UE4. key however, is that you’re not trying to rasterize vectors into sprites all time, only when an update is needed. I’m interested to know if there are reasons why you think would be a bad idea or perhaps just a useless one!! 
Cheers,
Wilhelm