Switching to https://github.com/babel/babel-sublime to get more modern JavaScript support reveals that the Flatland colour scheme doesn't work particularly well.
To check:
Install Flatland Dark as a theme + colour theme
Install "Babel" from Package Control
Open a moderately complex JavaScript file
Switch syntax to "Javascript (Babel)"
Compare with either of the "Babel" colour schemes
It seems there are several subtleties not being handled by the Flatland colour scheme.
The problem is that the Babel colour schemes look awful in Flatland and Sublime looks awful without Flatland. :-/
Switching to https://github.com/babel/babel-sublime to get more modern JavaScript support reveals that the Flatland colour scheme doesn't work particularly well.
To check:
It seems there are several subtleties not being handled by the Flatland colour scheme.
The problem is that the Babel colour schemes look awful in Flatland and Sublime looks awful without Flatland. :-/