Yes, the threads in the pre-release forum are here to present new features which the developers are currently trying to implement. The newest pre-release can always be found on the link in this thread (
https://forum.cockos.com/showthread.php?t=22836) so the users can try the new features out and give feedback if they work correctly or if something is buggy, give suggestions of how they could be implemented differently or sometimes discuss other closely related features that could be added together with the features in question.
Also it is important that if users find anything that doesn't work correctly anymore in the current prerelease that they share the information there so the devs can see if they have accidentally broken something by adding a new feature and fix it before the release.
Anyway it is NOT a feature request section so it is intended to only discuss features that the devs are currently working on and bug reports related to those features or the pre-release in question.
Not all features make it to a final release though, the devs take care as much as possible to release an official Reaper update only once the new features work correctly.