Posing such a question in the context of image and file uploads may be fine.  However, if we attempt at recruiting editors saying that Wikipedia is a means to have their voice heard then we risk compromising our NPOV ideal by attracting the attention of the POVpushing blogger complex.

So I'd recommend not advertising Wikipedia as a platform for having "your voice heard" but as a place where the contributors' research work is appreciated and read not only by a community of dedicated users but also a part of the 400 million+ unique visitors each year.  Though I know "having your voice heard" sounds far more sexier but partisan POVpushing is a serious issue on en.wp and tends to drive away far more contributors than anything else.

One of the reasons why our project tends to have far more teenage editors is likely because this is a demographic segment which has still not formed strong opinions on different subjects, and therefore are more likely to represent sources accurately without misrepresentation, original research and original synthesis.  Older people have far less patience for a project that adamantly gives more weight to third party reliable sources and scholarly research and rejects original research and synthesis.  Some of the users who get banhammered by one of these administrators ultimately criticize the project saying that it is run by pimple-faced teenage school-boys with too much time on their hands. :-)