In most places in the theme, you can change the settings for desktop, tablet and mobile. However, there are a few places where you can only choose between desktop and mobile. The main one that this causes issues with for me is the Article Background Image, but there are other places that this applies.
If possible, it would be great if in every instance where you can customise anything depending on the device size, that you can have all three options.
On tablet, if you have two components next to each other, they stack on top of each other. This is not something that you can override (that I am aware of). This causes issue with the above lack of customisation, because the Article Background Image will be the same across Desktop and Tablet, but the content within an article will be a completely different ratio of height and width.
If possible any place where you can customise based on device size, can it please be for all three device sizes, not just mobile and desktop?