I wouldn't like it atop the Spire. It would be too far up and would require maintenance and take from the slimline elegance which is one of the main features of the Spire. If we were to put the Tricolour near the Spire I would prefer to take inspiration from the Washington Monument in DC which has a circle of US flagpoles flying around the obelisk.
That said, there are quite a few Irish flags around Dublin - the GPO, Leinster House, Áras an Uachtaráin, the Four Courts, Criminal Courts of Justice and several hotels, banks and retail establishments (most notably Brown Thomas on Grafton Street) fly the Tricolour.
That said, there are quite a few Irish flags around Dublin - the GPO, Leinster House, Áras an Uachtaráin, the Four Courts, Criminal Courts of Justice and several hotels, banks and retail establishments (most notably Brown Thomas on Grafton Street) fly the Tricolour.