"The Suspicious.Insight detection, therefore, is meant to inform the user that a given application is unproven and not yet well known to Symantec’s tens of millions of users."
This is not true. I've been in business for 9 years and I'm quite sure I have many Symantec AV users. Yet my app was still flagged on virustotal by Suspicious Insight, which basically says "We have no idea". Of course your USERS don't see it that way. They see "Probably contains a virus." (I did jump through Symantec's hoops to make myself no longer "suspicious", whatever that is supposed to mean, but have no way of knowing how many dollars Symantec cost me with this nonsense before it was corrected.)
Thankfully virustotal has apparently dropped Suspicious Insight from their checks. Good for them! That still leaves (in your words) tens of millions of Symantec AV users who won't touch perfectly legitimate products from independent software developers.
This is a really bad idea, badly implemented.
David Hyde
DPlot Graph Software
(No longer suspicious)