"Needs more information"

I suggest that there should be a "needs more information" list/thing.

Probably not such a good suggestion, but:
Many coins aren't on Numista. There isn't much information of many coins either, but coins with less information have smaller chances in getting added to the catalogue. In some cases, finding a picture of the coin can be extremely hard.

I suggest that there would be a box somewhere on the "Add a coin to the catalog" page. If ticked, it would add the coin on a list of coins (for example accessible in the advanced search age) if this is possible.

This could possibly help in adding information about these coins.

Hmmm, this would be quite extensive list. In some fields in advanced search, you can put "missing" as well as you can put /no-picture/ into normal search. This way you can find many coins that need some info.