How many votes does a question have to have before it's considered appropriate? This process is about definition, not ordering the best questions. It seems to me, if you can get enough questions with ten votes each, that's already enough momentum to carry forward when the site becomes live.
Also, there are already many questions that seem like quite reasonable questions to me that aren't close to getting ten votes, that the questions that have got ten votes are being distinguished from. So there is already a significant level of discretion being expressed by followers.
I think it's a bit strong and unfair to question people's honesty in this process.
As I've mentioned in my comment to Lukaz L.'s answer, which, I realise, is anecdotal and not a scientifically proven assertion: People spend most of their time following their own interests and responsibilities which I think validates the latter part of his answer. On the topic of honesty, I've had a very brief scan of other proposals on Area51 but I haven't voted for anything outside what I'm following because I don't have the time or the expertise to properly and fairly assess matters outside my areas of interest.
So, in my humble opinion, numbers of followers are by far the main concern of any proposal and I see no harm in having a ten point threshold for deciding whether or not a question is appropriate and as I pointed out above there are plenty of good questions that won't make the ten point threshold.
The focus should be on how many such threshold questions should carry a proposal out of the definition phase. Some of the potentially super high voted questions will already be here and if we have enough followers with enough content more will surely come.
Is this really how the other established SE sites are measured? By their questions with really high numbers of votes?
I don't believe anyone's honesty is in question here. Oh, and by the way, there are still 4 votes going to waste on the Mathematics Learning, Studying, and Education proposal.