GFA pretty much ended terrorism, NI citizens gained rights to be whatever nationality they prefer to be, and an agreement was made that NI can trigger a referendum to join Ireland when the support for it is high (right now it isn't, though, staying in the UK wins by 7-30%, depending on the poll, with most being in the 14-23 range)

That's certainly a lot better than TNG's predicted course of history - a ramping up of terrorist attacks to get what a minority political opinion (at least in our universe, but maybe it's more popular in the ST universe) wants, and turning NI into a warzone.

The GFA is one of the best examples of Picard's entire argument in that episode - that terrorism can be avoided if we engage in good-faith diplomacy and political powers are willing to compromise.

Pretty ironic that NI was used as an example against Picard's logic in the episode, but actually ended up being an argument for it.