From what I gather, existing accounts will not have the option of "no credit card"
Not true. Please do not spread this around.
What is not apparent to some folks is that they should use their iTunes account ID if they already have one, and
not use their Apple ID if it is different from their iTunes ID. The configuration of your iTunes account is what the App Store account uses and I have spent the first day of the new App Store experiementing with the different senarios folks have posted here in this new forum with my account and it works perfectly.
What I would suggest is that if someone who wishes to use the new App Store does not have an iTunes account, then go to iTunes Store first and establish an account there. Configure the iTunes account as you want to use it, with a bank card or without a bank card, 1-click shopping or password restricted shopping, etc. After the iTunes account is set up to your liking then open the App Store and sign in with your iTunes account ID and password.
Dah•veed