Preface: the wand system was a pain for many years now, so common sense tells me that there are some fundamental issues with it. So probably it should completely replaced with something else but I don't have a ready solution right now.
Meanwhile, let us try to fix/improve the existing system.

1) "add shield location", "add aura location", "add barrier location" edges.
This was proposed by several people before and probably very easy to implement. I don't think that a re-rolling wand location edge will be good because it may actually make things worse :). So let us just stick to adding new locations. Those can be helpful for mages who can't find sleeks or their location is ugly for a specific class/cabal build.
Requirements: 30-40 level, some exp/observe points, some age hours.

2) Consider moving "detect artifact" to lower levels. Probably with some limitations like not detecting high level wands. This spell would be more helpful if mages could actually start exploring before heroing.

3) Some sort of quest that gives you vague hits about your locations.
With requirements like with edges: 30-40 levels, some exp/obs points, some age hours.