At the moment the article America is doing an excellent job of (1) being a disambiguation page for the various meanings and uses of the word America that might prompt a Wikipedia user to enter it into the search field and (2) attracting vandals and the like away from other articles.  The article Americas (terminology), on the other hand, treats some of the issues you've brought up above.  I don't see a reason to move the latter into the space held by the former.  At this time, the article Americas (terminology) does not treat how Spanish-speakers label various areas of the western hemisphere.  There is another article (Use of the word American) that does discuss how American is used differently by both Spanish- and English-speakers. -