Openlayers is huge! At 200k lines of code and 450KB, it is a significant overhead on a GIS-enabled modest ikiwiki site. It would be good to consider switching to Leaflet which is only 123KB (source)).
This would imply rewriting osm.js and probably bits of osm.pm, but would give us significant gains in performance... Leaflet is used by Flickr, Wikimedia, the main OpenStreemap map site and many others. --anarcat