Yeah, arguably you don't need schematic capture to make bag work but it is nice. I'm pretty bearish on KiCad for IC work personally but that's just my opinion - horses for courses. Yeah, my gut feeling is that it should be possible to make it work with magic. That's really the main place you want your automation anyway, the less custom layout work the better if you want to move fast. Personally if I was to extend bag I'd start just with magic and forget about schematic altogether. But I don't have the bandwidth for that so it's all hypothetical