While I don't feel as strongly about the Open Source route as @ThoPel, I would echo his comments about some sort of Unity plugin / easy integration, especially since it's new 2D workflow & toolset are quickly becoming huge in the industry. Kenney, if you can tap into this revenue stream, you'll be singing! I would look into Unity Asset Store, even as a standalone tool to start with, but then develop proper integration from there. People pay crazy money on Unity assets.
Also, if NXT would include some sort of Normal map creation tools (similar to Sprite DLight - http://www.2deegameart.com/p/sprite-dlight.html) in the future, Unity folk (a HUGE user base) would be buying it like hotcakes!
I don't really mind either way, just thinking of your cash cow! (also self-employed 😉)
Also, just saw that you've added some free 3D assets to the Unity Asset Store (from your packs), thanks!