Over on this side of the Atlantic, retiring numbers for legendary players is a big deal. In fact, no team in Major Leauge Baseball can have a player wearing 42 because Jackie Robinson's number has been retired for all teams since he broke the colour barrier in baseball.
James Forrest (the writer, not the footballer) wrote this blog item to argue the point against. My own opinion is that Celtic should retire the number 5 in McNeill's honour, but Forrest makes good points, and it's well worth a discussion.
https://thecelticblog.com/2019/04/b...driving-force-behind-celtics-legends-to-come/