Well, I'm afraid I didn't think much of Dublin City, so I just passed through it to/from the ferry terminal as quickly as possible. I traveled across the midlands area by way of Athlone, then mostly around Co. Roscommon, Sligo, Mayo, Leitrim and Cavan. I avoided most of the big towns, so I guess that's why it seemed that lights were rare. (Never got as far south as Cork or into any of the other big towns such as Galway or Limerick.)
The flashing amber and red signals you describe sound as though they're another idea that Ireland has adopted from America. In many U.S. towns you find that during quiet periods the lights at an intersection are switched to flashing amber and flashing red on the thru-route and side roads respectively. You'll also find places where there aren't regular traffic lights but where they have installed flashing red lights to emphasize a regular STOP sign.
I agree on the peculiar U.K. red-&-amber phase. I've never seen the point of it either, and all it seems to do is encourage the more impatient driver to jump the line before green. We don't have the red and amber arrows that are used on American lights either, only the green arrow.
