Redefining the whole color palette can be postponed...
But being able to choose the background (SchemeColorName.Background) and foreground (SchemeColorName.Foreground) would be definitely very useful!
At work we have an (very) old Compaq/Digital server under Tru64 Unix with to manage 279 SUN Solaris servers in batchs but the guy who wrote the scripts used black text everywhere 
Maybe his terminal was configured with a grey background or he worked on an old amber monitor 
So if you can't change the background color, it's very difficult to read black text on black background 
As this server use the old SSH 1.5 and not th 2.0 protocol, Royal TS can't connect to it as Rebex don't support anything else than SSH 2.0 but... who knows our guy may have written other script elsewhere 