Keyboard/mouse is "officially" not supported yet, Microsoft did confirmed that it will come, so we don't have to talk to Microsoft anymore, just wait...
In WarThunders case its probably more a fortunate bug then a design decision. ( I don't argue its awesome, since, i use it alot)
As soon as Microsoft fully officially supports Keyboard / mouse officially, i have no doubt Frontier will look into it.
It's only a matter of time.
But then agian, I dont need it, my HOTAS configuration can do it all, and with 3.3 I tent to use my right systems panel more as well.
And, how many buttons do you need the system/Galaxy map?
While in map mode, i still have the majority of my buttons empty, dunno what ur talking about.