Li Shenron
Legend
mooby said:I mean, a GreatClub is basically a large club, so why not, right?
Strangely enough, the Great Club was not even added with the errata into the Druid's weapon list. Somehow, the sage has tried to avoid explanations on why some weapons are forbidden and some other not by saying that it is mainly at DM's discretion, or a campaign issue.
Effectively, the way to allow/disallow an armor for a Druid simply if it contains metal doesn't work at all with weapons (see Scimitar, Sickle and spears). Another common way is to decide if the weapon is too much handcrafted, such as crossbows, but definitely the greatclub is simple enough.
I think that a Large Club or Large Scimitar are different weapons than Club or Scimitar for the purposes of proficiency, but not for the purposes of spiritual oaths; so, if your DM doesn't let you use the Greatclub (let's wait for the revised PHB for possible news), ask him about those other two.