Why does 0-conf need to be made safer? I used 0-conf 100x on Satoshi dice just fine. 0-conf is not 100% safe and not meant to be. Merchants accept that small risk for more business
Keep in mind that Satoshi dice uses your transaction output to pay out your winnings, if you double spend the payout will be invalid aswell.
o-conf (InstaPay) is completely risk free for online merchants shipping physical goods. If the transaction is not confirmed you simply cancel the order and don't ship the product.