https://www.uscis.gov/news/news-releases/uscis-updates-policy-guidance-certain-requests-evidence-and-notices-intent-deny
A heads up for everyone who is planning to apply in September onward:
Effective September 11, 2018, USCIS officers will be able to effectively deny incomplete applications for adjustment of status (or any other petition for an immigration benefit) without having to send out any requests for initial evidence first. That is, if form instructions require the applicant to attach certain evidence (e.g. birth certificate, tax returns, an affidavit of support etc.) and this evidence is not included at the time the package is submitted with USCIS, the petition may be denied on the spot. So it is very important to include EVERYTHING in your application when you file it. I read a lot of people choose not to include the medical exam form, because they don't want to pay twice in case if the interview takes too long to be scheduled - looks like this may not be an option anymore.
The memo says officers 'will be given discretion to deny applications" meaning that it will be up to them to decide if they choose to send the RFE or not, so it doesn't seem like RFEs are eliminated altogether (i.e. the officer can still choose to send an RFE as opposed to denying the application), but still, it is important to be prepared for the worst.