I'm not sure what the plans are for further development on the core Layout module but it would be great to see it develop into a fully fledge visual layout builder. WordPress for years has many choices of a visual builder and Drupal is heading in the same direction as it brings many benefits to both the end users and developers.
Backdrop is always talking about making it easier for the end users and there's nothing more easier than to have the tools to create and manage your own site layout and theme templates without coding. Just take a look at the success of Squarespace but Backdrop has more advantage since it is an open system that any developers can build on top of it to further extend the Layout module for additional features. So perhaps this should be a priority for Backdrop since it would solve most of the usability goals Backdrop has set out to achieve. Also, getting this out before Drupal would put Backdrop ahead of the game. Sure Drupal has already launched Layouts but it still has a long way to a finished product.
One thing which i think limits the use of Layouts is the pre-defined layout templates. Why not get rid of that and allow end users to define the own layouts on the fly? One of the Layout builders i have been very impressed with is DXPR (formerly Soopertheme) https://www.youtube.com/watch?v=AIqGHm5UfBo The only thing i dislike is having to activate this from the managed display page. It should be done with the Layout page like this (demo of Layouts in Drupal 8): https://www.youtube.com/watch?v=qUkpzSllO30 and render Layouts either for site-wide, certain content-type(s) or specific node pages.
In addition, a combination of both would be the ideal way. Layouts module works like how you see it in the Drupal 8 demo (above link) but without the pre-defined layout templates to choose from. Instead, the use of visual layout builder to build out the layouts (columns and rows) on the fly and add content is a better solution, imo. We can go a step further to allow for adding widgets (tabs, social, forms, events, quick links, image sliders and etc), not just blocks. Pre-defined layout content sections would be nice too for those that want to quickly add a section (ie, pre-defined header or footer section) without spending too much time to create them. Or even custom pre-defined layout content sections that can be saved and reuse (maybe on other sites as well).