If a voter's incompetence could lead to undesirable metagames...
Undesirable for who? You, or the voter?
Keep in mind that just as you will have a desired metagame, so too will everyone else who plays OU/UU/RU/NU/PU/Double/LC. I understand there has been a lot of controversy of the 'worthiness' of voters as of late, but keep in mind that, so long as it is a public vote,
everybody's opinion is equally valid. You may disagree with their competence, or reasoning, but they're affected by the outcome just the same as you are.
What's nonsense is this argument that people have "plenty of places to participate elsewhere." Suspect votes affect
all players, and as such, it is not a question of participation to the site in this case - as while smogon is very much a oligarchy, suspect tests are democratic, both in intent and in execution. And while you may think the voter who votes to keep Aegislash because it's the core of many of their teams a idiot who isn't voting the right way, if they put in the time to show that they've had experience with the meta and thus have a vested interest in the outcome and are allowed to vote, their vote is just as valid as yours is.
That's why it's a 'vote.' You can't have a 'wrong vote' if there are only two options - otherwise there's no point in having a vote in the first place. If there is
ever a case found where the "wrong" suspect option was chosen, that would be a direct failure on the council's part, not the voterbase - because if it's that clear cut that there was a 'correct' decision, the council shouldn't have put it to vote in the first place, and should have made an executive decision.
As a pre-emptive disclaimer, I do not personally believe that you should be hypothetically voting to keep Aegislash in the metagame simply because you really like to use it, and I don't believe such votes are very intelligent. Regardless, they are still
valid, just like a vote for Donald Trump because you think it would be funny would be valid in a hypothetical United States election where he was one of the candidates for presidency. Valid doesn't mean smart - it just means a qualified voter's vote is worth and should be worth the same as anyone else's, because regardless of what you think of their reason for voting, it is still their reason, and why they vote in that way in the first place.