Can't really see the idea of readable text catching on, not until the dreaded day when ATC has direct control of aircraft via data-link!! Anyway, who would type the messages on the ground - wouldn't want to trust voice recognition software! How would you get the information about other aircrafts' relative positions/altitudes? Even when it's busy going into LHR for example, I try to keep a mental picture going (sometimes a bit fuzzy though!).