Sorry replying to my own comment here, but this needs to be said. THANK YOU KiCAD developers. Yes it has issues but I am very grateful, comments above aside.
That said, I am very happy to see new entrants, like Horizon. I watched a presentation by the author in the 2018 FOSDEM and it looked like a great idea even back then, I'm going to try it for my next project to see how it has progressed.
Wayne Stambaugh, the KiCAD project lead, was in that presentation, and they're very much aware of the problems KiCAD has. They're working in that direction, as KiCAD 5 no longer requires you to export/import the netlist, I believe (I'm not sure because I reflexively always do it anyway).
One of the first questions they had towards the Horizon developer was "why make a new tool instead of contributing to KiCAD?", and the answer, IIRC, was "It was easier to make my own", which sounds reasonable given the amount of innovation that went into Horizon and the constraints a project as widespread as KiCAD would have, regarding backwards compatibility etc.