That does bring a good idea to mind.
Can we have a customizable sidebar?
Say, I don't want to always see my stats and health. Instead of leaving it out entirely or relocating the function elsewhere, can the sidebar element that displays those parameters simply be... turned off? Like docked settings displays in some art programs. One button press to turn it on or off as needed, so you can leave it off if it's not relevant, but don't have to check some other screen if you do need to track it.
I.e. have the sidebar displays grouped by function. There is the health section, the creature tracker section, and the surroundings and status section. Arrange the sections so that they fit neatly into strips, with no section occupying the same horizontal line as another one. The health section displays the six healthbars, arranged into a 2x3 block so that they occupy less vertical space. The creature tracker shows the big compass and huge legend of visible creatures. The surroundings and status section displays all the actually essential things you want to always see - your pain level, status alerts for thirst/hunger/sleep, the morale level, and the bionic power level if appropriate, plus the mini-overmap, the location info, weather, and time of day - grouped together because the minimap is fairly large vertically, but occupies little horizontal space. If it can be customized more thoroughly than that, it'd be quite good, but even this setup - mechanically rather simple, in my opinion - could work for those of us who want to see less space taken up by status displays.
Conversely, it can be done the other way as well - more things could be displayed on the sidebar, like skill rust warnings. The sidebar already functions like that to an extent - new panels pop up when a weapon is being targeted or an item is moused over. This could be an extension of that functionality.