I wonder if Kbin would be open to being the image sharing community and this community can be for text posts?
I come mostly for the info and to share questions/answers. Some come for the images. Since lemmy doesn't have many powerful tools yet for filtering, it might be worth partnering with the Kbin to make an impromptu filter to keep both separate but interoperable.
You'd have to talk to the mods. But I think a general issue is that cool pictures appeal to the widest range of users, so an image-based server becomes popular. And people want their posts to be seen, so they post to where they think they'll get the most views.
The only way your suggestion could work, I think, is if both servers strictly allow only one type of content.