When we switched to Grunt 3-4 years ago it was pretty new and well supported.
Times have changed and Grunt is now the old-man of the build process.
It has become slow, and cumbersome, and is not ideally suited to our needs any more.

We should look to see what alternatives are out there and if one of those would be better suited to our new build process. Options include:

1. webpack
2. gulp