This proposal would authorize the Committee to add up to two additional works to the final ballot. The Committee's selection would be limited to adding not more than two works from among those works that were among the top 15 nominees or that appeared on at least 5% of the nominating ballots cast in that category.
I would not necessarily require the administrators to say that they had exercised their rights when making the finalist announcements. Historically, there have been as many as eight finalists on the ballot due to last-place ties. While historically such longer-than-five-finalist ballots have been explained as due to ties (this happened once in the Retrospective Hugo Awards this year), I could certainly see Administrators not saying why the ballots are longer and making us wait until after the ceremony, when the post-award report would make it clear.
This proposal has the advantage of not requiring an additional round of voting, and does not triple the number of finalists. The biggest disadvantage is that it requires the Administrators to make subjective judgement calls, which historically they are loathe to do, and for good reason.
I can see the prospect of Committees expanding to include members brought on for their literary judgement rather than for their administrative skills. Such members would of course be ineligible for the Hugo Award in the year they were on the Committee, like all of the others.
Although I wrote this as "plus 2," there's no reason it couldn't be 3 or 4 or even 5, although I'm leery about doubling the size of the final ballot.
There is precedent, albeit an extra-legal one, for Administrators augmenting the ballot. In 1989, a single category came into question, due to a large number of nominating ballots being submitted simultaneously, paid for by consecutively-numbered money orders, and in the names of people for whom it is unclear they knew they had memberships. Apparently all of these ballots named a single person in one category and nominated nothing else. (There is no implication that the named person had anything to do with this scheme, and some implication that it was the result of overly enthusiastic fans of that person with more money than sense taking advantage of the system as it then existed.*) Instead of simply disqualifying the ballots, the Committee elected to add a sixth name to the finalists in that category. Shortly thereafter, one of the finalists withdrew.
Just like all of the other proposals out there (including the two up for ratification this year), this is no panacea, and I think there's a real concern that letting the Administrators exercise subjective judgement over whether extra works should be placed on the ballot undermines the popularly-selected nature of the Awards. On the other hand, I do recognize that we currently have a situation where people have not been nominating in good faith, and there are people who I respect but with whom I do not agree who think the Administrators should be intervening dramatically, rejecting individual ballots or finalists. This proposal seems to me to be the least-intrusive way of letting the Committee do something without totally rejecting the nature of an award selected by the members of the World Science Fiction Society.
*In those days, you could join at the time you nominated, right up to the end of nominating, just as you currently can do when you vote on the final ballot or on site selection. It was in reaction to this particular case that WSFS adopted the rule that you have to be a member no later than the end of January in order to nominate, rather than up through the end of nominations. As a further reaction to the cut-off date, WSFS extended nominating (but not final ballot) eligibility to include the members of the previous Worldcon, in order to not disenfranchise "regular" members who tend to join every year but who might not have gotten around to joining the current year by the end of January. Adding the members of the subsequent year's Worldcon was a later addition, and has only been part of the system since the 2012 Hugo Awards.