Use CSS Grids and Flexbox for Layout
It's 2017, you really shouldn't be using <table> for layout!
SharePoint should use Grid and Flexbox for layout of not just the Ribbon, sidebar, navbar etc but for List forms too. This would clean up the SharePoint HTML and CSS considerably as well as making it easier to customise the layout of forms.
(Sure, there's an argument to be made that there's a semantic relationship between form input and tabular data, but I'm pretty sure the 'tables for form layout' is just something carried over from earlier versions of SharePoint needing to serve browsers with poor standards support.)
Hi – thanks for your input. Technically this has been already done at SharePoint Online where all the new experiences are natively responsive, including site pages, site contents, list or library experiences. We are also working on including these in the future feature packs for SharePoint 2016 on-premises. We are not using