Actually, GFDL quite specifically *requires* that if an article is merged into another one, the old title has to be kept as a redirect in order to preserve the edit history.
If the old title is bad, the article can be moved to something else in order to keep the history of the merged information. This was what done for a lot of "AKFD" articles a while ago since people objected to the titles more than the content of those pages. If you want to merge [[Poisonous influences of fruit]] into [[Kumquat]], you can move [[Poisonous influences of fruit]] to [[Talk:Kumquat/Page history]] and delete the redirect from [[Poisonous influences of fruit]] without losing anything as long as you cite [[Talk:Kumquat/Page history]] somewhere so people can look up the original authors of that part of the article.
Angela