I don't say that designers should program instead of using their tools. What I say is: Stop the craziness of 50 different projects which give you some set of icons. Each a little different but each repeating things over and over again. Let's define one framework and go from their and satisfy 95% of all projects.
Let's stop the craziness of 50 different programming languages which all bundle slightly different sets of features. Can't we just put all the features in one language?
The reason to use one icon set on a web page is that the icons look good together. Putting a bunch of different icon styles in one set defeats this. A good designer has the skills to bust out Sketch and make another icon in the same style if they need it, and then contribute it back to the set for consideration.
If you're not able to do this, there's always http://icomoon.io/app/ which lets you bundle icons from different sets into one font.
And who, among the people who actually design and build icons, would care?
Hint: they use Illustrator. They're going to keep using Illustrator. They're not going to stop using Illustrator so you can have a marginally easier Github workflow.
