Especially with higher resolutions the sidebar is.. very empty..
Like in Settler IV it might be possible to put optionally more infos in the empty space of the sidebar (like unused pioneers/constructors, current minerals, oil, gold reserves...).
And to think further, maybe it would be awesome to integrate a building menu (depending on selected unit) and/or to add the context menu to the sidebar (so the flow could be more smooth because you can hold the overview of the map and the extra building window is not necessary anymore).
All these features could be enabled in the settings-dialoge (y/n for modern/simple maxr hud).!