1) Auto GOPATH detection: since all code is located underneath a canonical GOPATH, if the GOPATH is not set, traverse upward a few directories until you find one with a "src" folder in it. This means that I don't have to launch it from a terminal and deal with environment variables. Also, I use a GOPATH per project, so as long as each window auto-detects its own GOPATH, that works great.
2) Cross-compile all the tools (gocode, etc) for the most common platforms, presumably windows and mac, and include them in the extension so that it doesn't rely on auto-install or whatever and just works out of the box.
#2 is something we definitely want to do with the VS Code extension as well. https://github.com/Microsoft/vscode-go/issues/5
#1 is also a good idea, we currently offer a per-project setting to configure this, but could also guess better in the case that no GOPATH is set.