A simple way to quell the fears that people appear to have is to publish two things:

1) an anonymised list of investors and invested amounts (so people can check how much is invested)
2) the cold wallet address (so people can check you still control all invested coins)

I think with those two things people are able to satisfy themselves that everything is as it appears, and that there's nothing "ponzi-ish" going on.

A clear statement as to whether you consider new investment as profit for old investors would also help a lot, I'm sure.  Is it possible for an investor to make a profit on his investment if there are never any bets placed?  Some people seem to be saying it is.