Normally it takes me tons of time to kern in FontCreator, because for each pair I need to create the pair using my mouse, searching for glyph 1, searching for glyphs 2, and only then kern the pair.
I want to show you:
How I kern in GlyphsApp: https://www.loom.com/share/630a386ff5cd4ae593f79310bb04dd81
How I kern in FontLab7: https://www.loom.com/share/9d0c09b4a9e4469db6da8e60bffb4723
How I kern in FontCreator: https://www.loom.com/share/a89343088fef46a5a809d61cda2b1530
My suggestion for a solution: https://www.loom.com/share/b0010a5f2c5f469a9b0dde1cf50fcab1
If it will be possible to implement this kind of feature, It would save me hours of time for each font, no kidding. 
In my opinion, this feature should be very prioritized (but only after variable fonts are completed).
Let me know what you think! 
Elron