vanHorck,
In many airports the display boards are bespoke-designed to display a set of information that does not include lengthy messages such as yours. However - revamped (i.e. modernised) and new airports use LCD displays that tend to allow the displays of longer messages, but the airport systems may not necessarily be as advanced to display such messages. Even if they are, how do you turn a delay that is due to legal requirements (i.e. late arrival the previous night with legal requirement to rest 6 hours plus travel) into a short and sweet message?
"due to crew scheduling" is a terribly vague message.
"due to late arrival" doesn't work when this is the first flight out.
"due to legal requirement" also is terribly vague.
Considering that I am in the business of usability, I know that people don't read long messages, hence security messages being... short. sweet. blocks. of. information. that pax. can understand. You get my drift.
I have to agree with Paxboy that the airline who manages to get a system up and running that allows their ground crew (or the contracted out ground-staff) to display the reasons for the delay, will be the one with the most customer satisfaction where delays are concerned.
From past experience, many US airports (I haven't flown into MIA, so I don't know the state of the terminals there) still use antiquated CRT 15" (if that) displays that only show the airline, the time, and the gate. Structural investments like better PIDs (Passenger Information Displays) are LOW on the priority list.
Airports where airlines have an exclusive terminal (ironically, BA's Terminal 5 or JetBlue's JFK terminal are perfect examples), more expansive displays could very well be possible, provided they are controlled by the airline specifically, and the airline is always on top of why flights are delayed.
S.