It's not that the pre-alpha Diaspora has insecurities that bothers me, it's the whole execution. What I really would like to see is a documented protocol - based on XMPP or some other established, well-tested protocol would be good, but if not then at least something. Once you have that protocol - which tells you how Diaspora "seeds" communicate securely - you can let others build their own implementation, using Rail…
Nobody stepped up to write a decent client, and the product was judged (unfavorably) on the merits of the reference implementation.