I've served on a few boards in my time, and if I wanted to "improve the set of skills and the diversity contributed by newly selected trustees" this is not how I'd try to do it.
Yes there are likely to be certain skillsets that you want on a board, but that's a key reason for having independent members. A few years ago I served ten years on the board of a charity local to me, we had certain skillsets that we needed on the board, including a retired Medical Dr and a couple of people who understood investments (our endowment was similar in size to the WMF). We usually got such skills by recruiting independents who had the skills we missed but thought we needed. Why else would you want "independent" trustees?
As for diversity, yes I can see a need and a route to do this via the community places. But there are ways to do that that retain open elections, for example, if you want to reserve a seat for "someone resident in sub saharan africa" you can either create a separate geographic or virtual constituency, or just use STV but modified to include the most popular candidate who meets the diversity criteria you chose.
WSC
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