Hi Michael,
If the community decides it doesn't want to use Pending Changes, but the feature remains enabled, it will be a constant battle to police usage of the extension. Why should the extension remain enabled on the project if its community decides not to use it? That frankly makes no sense at all. I understand the argument that the community can just decide not to use it and punish people for doing it anyway, but that seems like a pretty silly way of going about things.
If the trial said the extension would be turned off, and it didn't get turned off, then whatever the reason... Someone from the WMF, who is making the decisions here about enabled vs. disabled, should acknowledge that the rules changed and that concerns and irritation as a result are valid. Waving it off by pointing to polls that clearly don't establish the Wikipedia norm for consensus? Not a great idea, in terms of internal PR. Start by apologizing for setting false expectations, and move on from there.
As to participation - the PC polls got as much participation as any poll of any type ever has on Wikipedia. I suppose you can set the bar higher, and say this particular poll is so important it should get ten times as many voters as a normal poll, but... I'm afraid the number of people involved in Wikipedia =/= the number of people interested in the meta management, and it seems like the polls got a pretty representative sample of the second group.
Finally, the folks objecting to discussing en.wp should think about how it feels to people who edit en.wp when, every time it comes up on Foundation-l, old hands on the list say to take it somewhere else. The list is by no means dominated by en.wp issues, and I think most reasonable people will agree that en.wp is by far the highest profile project and chiefly responsible for putting the Wikimedia movement on the map. The most major problems facing the English Wikipedia are challenges for the Foundation as a whole, and there should be a place for those problems on foundation-l.
Nathan