I believe your requirement to file a US tax return depends on your income level. Are you saying that the IRS is saying that if you didn't file taxes before and you own no tax then you don't have to file those tax returns retrospectively? Sounds a little "chicken and egg" to me.
As a US citizen you are required to file a US tax return, reporting your worldwide income. There are filing income provisions based on your status of single, married filing joint, head of household, etc ...but basically, if you earn over $5,000, you should be filing.
What the IRS is offering here is filing relief for those citizens who live off shore and owe no tax, usually because of the foreign income exclusion or foreign tax credits. Instead of filing for the last 6 years, you only need to file for the past 3 years.
Also, many people who have over $10,000 in banks accounts have neglected to file the FBAR form because they did not realize it was required. There have always been pretty stiff failure to file penalties associated with that form. Starting September 1, as a part of this program, they are waiving those penalties.
THE FINAL RULES HAVE NOT YET BEEN ANNOUNCED ...