“There’s been a lot of discussion of copyright, and how game mechanics are not copyrightable. Some folks suggest that this is basically the entirety of 5th edition. Is that correct?
As with most things in law, the answer is “maybe”, and that it’ll be expensive to sort out. I do a brief discussion here of some of the issues, and why legal uncertainty is on the side of Hasbro/WotC rather than the 3rd party designer.”