Ninja Dolls, adding 2.5% adena each, are pretty useless. Considering what you have to give up to use one (other good dolls) they're not worth owning. A significant buff to their effect could make them useful to the point that people actually use them. Adena rates on this server are low, low enough that you could have each doll give 25-50% bonus adena and still only make them worth using in very high adena places (such as Boss Island). It wouldn't change much else, hunting real bosses would still yield FAR more money than anything else.