Jamie sorry I am trying to reply to as many points as possible without getting too personal with anyone. I don't think there is any direct value in mere representation. Afterall a lot of unpleasant, violent, evil things take place in the world and we don't feel they should be represented in toys, role models, education etc merely because they occur. Education has an evaluative component, we pick the appropriate role models, we surround ourselves with the right examples, we encourage the correct behaviour, because we want to encourage in a specific direction not a random, general one.
Of course there is a place in playing and education for diversity. Toys should have people from all races, ethnicities, abilities/disabilities, genders (to include people of one sex dressed in outfits of the other gender and so on), families with different compositions (single parent, same-sex, grandparent-carers), and lifestyles (women doctors, men nurses, women builders and men nannies to name but a few). However, diversity is not an excuse for unthinking acceptance of ANY other lifestyle.
The type of covering depicted in this toy is not a national costume or a regional style variation, it's a religiously mandated requirement you can get stoned for not wearing, that applies only to women and is one aspect of many ways in which women's lives are severly restricted - hence not a decent role model.
None of this applies exclusively to extreme versions of Islam, here's a 'lovely' example of an extreme version of the Jewish faith:
failedmessiah.typepad.com/failed_messiahcom/2012/06/immodestly-dressed-woman-stoned-in-beit-shemesh-456.html
and an ironic move extremist Muslims seem to be in agreement that all the world's wrongs are down to women's dresses:
www.ibtimes.com/moroccan-woman-beaten-stoned-and-striped-salafists-over-revealing-dress-womens-rights-imperiled
desertgirl you don't find this type of dress amongst girls because it is not religiously required. Girls have to wear it from sexual maturity onwards.