The implementation in the beta, as best as I could grasp it from the stream, is as follows;
* The Decisions that are currently enacted based on a string of conditions (completed Idea groups, certain advisors, monarch stats, finances, one-time monarch point cost) are being transformed into Policies.
* Each combination of any two completed Idea groups enable one Policy. If you have completed, say Administrative and Diplomatic Ideas, that will give you a different policy than if you complete Administrative and Economic. If you complete Administrative, Diplomatic and Economic, you get access to three policies (the combinations of A/D, A/E, D/E). That means there are 105 possible policies, I think, and you get access to more the more Idea groups you finish, at a max of 28 policies per game if you complete all eight idea groups.
* The policies require an upkeep cost in monarch points, similar to excess diplomatic relations and army/navy commanders.
* These Policies are toggled - that is, you can enact one, and later remove it when you're short of points, get a worse monarch or don't need the policy anymore.
Apparently, the reasoning behind this mechanic is that players have an abundance of monarch points (can't say I've ever experienced that luxury), and that the new system will mean an active component where you enact a policy for when you need it. This latter part I like - you can now enact the Witchcraft Act while converting Rome, then remove it (and its global RR component) once the job is done, or enact a policy to boost discipline while fighting an important war, etc.
However, this system can quickly gimp non-Western nations even further, as those nations struggle to keep up as it is.