[Edi]

Site searching is perhaps the most important part of magic diversity, because it allows finding indie mages with better magic in specific paths. So you only really need 1 level of astral or death but lv 2 in elemental paths and nature to get sites, but it doesn't guarantee access to the more powerful magic. It certainly helps, though, because the random site distribution means you might not have almost any gem income of your most common magic paths.