Good post Rab-K.
Cowpatz, as suggested take a day off work and visit a centre, you'll probably find it a real eye opener.
Part of the problem with the data link is that it has to be all things to all men. Any changes which might have to be made to satisfy one section of ATC have also to be evaluated for any repercussions in another. Also the controller's kit has to be compatible with the rest of the system - ideally no larger than a Tx switch! - unfortunately it is often piggy-backed onto another system and the resultant complication often outweighs any benefit and therefore delays the program's implementation