As a generality I would say that reliance on SSR data since the 70s, by ATC certainly, has diminished the ability to work with minimal data. Think Word Processor VS. Pen, email VS. Letter.
I've had numerous situations when handing over aircraft to another Mil ATCO to hear bleats such as "I don't have a flight plan for him" or "I can't see his squawk". All one actually needs is a primary return, in the right location on tne right heading, for identification from another controller. Then just "Take 5" or coordinate - it's not that difficult.
Sadly, automation now seems to require innumerable additional bells and whistles to achieve a safe, orderly and expeditious flow of air traffic.
[/rant]
