The problem is that while this makes sense, it's not as easy to understand and explain all the so-called "corner cases" to lay people, and the feature may end up being misused, if present. At least now we know how voting works -- it's predictable and does not depend on whether some people chose to vote conditionally or not.
Introducing conditions always has the downside of muddling the main idea, even if it may be more efficient for some people.
My gut said this was an ill fit right from the start, post #2 to be precise, and on further reflection the challenges marrying the two only proliferate.