In practice, I think agencies won't be publishing any new regulations in the Federal Register for public review and comment. In other words, they won't be adopting any new regulations, as that is part of the process for crafting them. Perhaps more interesting, is the definition of "regulation" (Section 4). It "means an agency statement of general or particular applicability and future defect designed to implement, interpret, or prescribe law or policy or to describe the procedure or practice requirements of an agency" with a few exceptions. If I'm reading that correctly, this EO goes beyond regulations issued through the normal process via the Fedeeal Register, but can encompass nearly any "rule" an agency issues.
I'll be interested to read what others think who are familiar with policy issuance on this level.