It's not really clear from the documentation/README how this works under the hood, so for now I have to just go by what you're saying here until I have time to actually take a closer look.
First off, I will say that I'm not a great fan of godep, so I'm not looking to advocate for it. That said:
> Godep wants you to mangle with your GOPATH. For example, `godep save` saves revisions of packages currently installed in your GOPATH and `godep restore` downloads packages into your current GOPATH. If you don't have to pollute global GOPATH, you will have to change it. This works for some people, doesn't for others.
Your $GOPATH is a list of directories, not a single directory. This is almost never useful in practice (most people should just use a single directory as their GOPATH). However, for what you're trying to do here, that would be far simpler than introducing a third-party tool, especially one that requires adoption from all project contributors.
> Goop doesn't want you to worry about GOPATH.
The $GOPATH is technically not part of the Go language (spec), but it is a language-wide idiom respected by all build tools. I'd be very nervous about a project that eschews such firm idioms in favor of its own inventions.