I know changing layer order or number of layers completely ruins a webmap and removes all its popups but this time just changing the name in one layer in the mxd's TOC mulched it. I had thought that was fine, I think I remember doing it before and being ok. No! Seriously we need a "turn all popups on" button for a service, in the webmap in AGOL. It would save days a year clicking Enable Popup.. then waiting, because it snaps all the way to the top, and then back down... then up.. then down. Yes Server 10.3 allegedly fixes the layerID thing but still.. for us poor souls on 10.2 and below a turn all popups on would be so, so nice.