A brief summary of my opinion for JavaScript module management; ES6 wins.

1. Module Management
for ES6 Generation

2. - Resolve version conflict and keep them flat to
reduce resouce size(using Semver guideline).
- No compression by module provider for
optimization by user side.
- Some way to indicate package private to
prohibit invalide accesses can be better.

3. foo
bower_components
private
main
common 0.9
util
unused
common 0.8 bar
foo
bar
sub
app
ui
compatible
all(deduped) private main sub foo util bar ui app
all private main sub foo util private main bar ui app

4. - Modules never depend on specific
ecosystem.
- Loader will be work over defferent
ecosystems.

5. foo
bower_components
private
main
common 0.9
util
unused
sub foo
import common from '../common/dist/main.js'
import common from 'common'
base = ./bower_components
'common' => ${base}/common/dist/main.js
Module Loader
static dynamic

6. END

7. END