Just out of interest why would you be concerned? And if your sister was your brother would you be as concerned?
Yes, I would be concerned if it was my brother. I think it's because she lacks the cultural support structures. Within a Zulu culture it's accepted as normal and is treated as such. She would gain status and people would support her marriage. Within the jewish culture from where she comes, she is more likely to be ostrecised and given a hard time. It would require a huge paradigm shift for the entire family.
At the risk of being flamed here, this is my opinion only and I don't want to offend anyone - I think it's highly unlikely that Islam and especially Sharia law will control the global economy any time soon (if ever).
Having said that, Islam as practiced in the modern context (without some of the more unsavoury practices) and as a less fundamentalist mindset is in my opinion a culture which promotes learning, sharing, upliftment of the poor and even religious tolerance. I don't think much would have to change in that type of scenario and I certainly wouldn't have a problem going without an extra wife or two if it meant I'd be taken more seriously in a global economy
I too think it's highly unlikely that Islam and Sharia law will gain global dominance, I was just trying to make a point that majority opinion isn't necessarily a good reason to turn your back on your own culture.
I also don't think there is any evidence that having only one wife will mean JZ (or anyone else) would be taken more seriously.
Sometimes things need to be challenged. 50 years ago, the thought of a president who had been divorced and remarried would have been unthinkable. These days it's not such a big deal.