Importing a less file from a package is almost impossible.
Dropping a bunch of less files from a library you downloaded somewhere (modified bootstrap, bootstrap theme, etc). You would need to rename a lot of files and remanage the imports everywhere. This is annoying and prune to errors.
I'd add to the primary goal here "SUB-SECOND BUILD TIMES". This is our stated goal at Respondly - it's too expensive not to have extremely fast builds (particularly for impression of quality for the Meteor framework), and so I'd really encourage you to get build times up on the primary set of goals.
the build performance is not part of this week's work. Right now we want to solve the problem of sharing Less files between packages etc. The performance is a priority too, but it comes after the API designs.
It doesn't look very different from the current Less build plugin. It probably suffers from the same problem discussed here. It does have different extensions "build.styl" and "build", and it uses autoprefixer, other than that, it is not very different.
What are the challenges in getting Atmosphere packages to npmjs.org and how can we solve them? For both MDG to work out what's needed in tooling and for eventual good docs for the community package authors.