B. Pull random numbers from a hardware RNG. Could use a site such as random.org (my concern though would be trading the risk of the OP for risk of a new entity). This random # would be used as the server seed (cannot be used as the seed # for hashing since would not be provably fair).
why not pull random numbers for use as (additional random to) server seed from the blockchain (every block or so)?
That actually seems like a pretty good idea. What you think Doog? Would that be difficult to implement?
A player can randomize their server seed as often as they want. Blocks are many minutes apart most of the time. So the blockchain is not a good source of entropy in this case.
Even if you combine the blockchain with another source of entropy (the servers RNG for example), the quality of your random number generation is still limited by your second source, because if that contains a flaw, players have the option to gamble quickly enough and place many bets before the next block is found.
I honestly doubt that the source of entropy used is insufficient in the case of J-D, but even if it is and it needs to be replaced, it needs to be replaced with something that doesn't have a rate-limit like the blockchain.