Could be.

We build something similar using node.js and it's working quite well. Perhaps we can open source that someday...

nginx+lua can be exceptionally fast. It's the basis for OpenResty, which is a consistent top-performer in the Web Framework Benchmarks (http://www.techempower.com/benchmarks/)

Webdis is a neat project, but I'd be a bit wary of deploying a custom HTTP server written just for Redis interactions. Nginx is battle-hardened.