There are some important things to note (from the 119 page pre-announcement-I just finished reading):
1. With the new expansion it means that not only spouses and parents of US citizens but also spouses and parents of LPR's can apply for the provisional waiver.
2. DHS has eliminated the time limitation, therefore those that were previously ineligible because the Dept. of State had acted to schedule the interview prior to Jan 2013 are now eligible to apply, so long as the case has not been terminated. If the case has been terminated you may apply to have it reopened. Once reopened you will be eligible to apply for the provisional waiver.
3. DHS has eliminated the "reason to believe standard". This means that it will be even more important for immigrants to consult with a good immigration attorney because they can presumably obtain a provisional waiver, depart for their immigrant visa interview and then be denied if another ground of inadmissibility applies to them. The provisional waiver only applies to inadmissibility for unlawful presence and if you inadmissible for another reason you will be denied at your interview and have to apply for a waiver from outside the country, if one is available for that particular ground of inadmissibility. This creates more risk for those that don't have good representation from the outset.
4. Having a child who is a US Citizen or LPR is still NOT enough to qualify for a provisional waiver even with this expansion.