I do actually plan to release Weekly/Fortnightly builds, with gradual improvements to see how players react to the changes, as I think it would be much easier to create a game that players enjoy with real user feedback than without, which would be a win-win situation for everyone. (the game itself will be a complex MMO so its not a stick run which wouldn't require that much feedback )
The problem of submitting it to the portal once as an early alpha and updating that submission is that nobody will go back to see it, which would defeat the purpose of submitting it to NG at all, as the whole point would be to get new testers for each new version.
I suppose adding it to the dumping grounds with free access, and creating a new topic for each new version in the forums seems the only legit option for now.
It would be great if the NG Alphas would be resurrected!