Perhaps this is too obvious, but where's "any two alternatives related to voting/XP"? (public vs secret; gain XP when downvoting vs lose XP when downvoting; must reply when downvoting vs need not reply when downvoting; unconditionally downvote all nodes related to XP vs don't downvote them; etc.) :-)
Re: Which topic it most controversial within the halls of our sanctimonious Monastery:
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