The title says it all basically. It is really exciting to see you're adding (or planning to add) passenger information systems to East Coastway and Long Island Railroad DLCs from Preserved Collection, I think not only I honestly appreciate it, I feel like it is another step towards immersion and realism! (and I hope others will follow soon) However, why not add PIS to GWE and RT as well since they do not even have working destination boards? I believe you should maybe treat it like the last polishing touches for the trains in GWE and Rapid Transit. Since both of those (the Talent and BR Class 166, not sure about the HST) were sort of prepared for future introduction of PIS - the displays are there, the buttons are clickable - it shouldn't be that big of a deal?
They probably will eventually but these things take time. They can’t add every feature to everything all at once.