Hi Chris,
my answer is not really related to Fordson but to the mockup in general.
I think I have seen this screenshot already approximately half a year ago and as far as I know it was made by Alberto Corado. It was definitely there before 3.5 was released and probably even before Bas Brands tackled the Bootstrap 4 stable upgrade.
Regarding the mockup, I don't have a strong opinion against anything within it. It looks sleek and up-to-date. Several of the navigation shortcomings which we have noted while using Boost in production are handled differently know.
What's saddening me is the fact that we don't see anything else than this single mockup. There isn't any public discussion about it which I am aware of and we don't know what the status of this revamp project is.
That's why I would just like to let Moodle HQ know: Please, just tackle this project now after the GDPR storm is over and let the community participate.
Cheers,
Alex