I will happily take feedback on how this should be adjusted so that we can meet our goals without compromising the privacy of the users.
Here's a suggestion: randomly generate a 32-bit unique identifier, store it in the Armory config files, and report that. It's not perfect, since someone with multiple folders will be counted multiple times, but it's pretty good.
Or just don't use an identifier at all and only send the stats once and keep track of whether they have been sent or not somewhere in the data directory. In the case of an update include the last version that it was updated from so that you guys can adjust your stats.
There is very little reason to need to have a unique identifer for each install. No other wallet does this that I know of.