The GDW lawsuit was actually mentioned in the podcast. Specifically, that Gygax used D&D spells with just their names removed. I don't recall who was saying it (Steve Winter, I think?) but they seemed to think the lawsuit was justified.
Here is
part of the complaint in question. It does list a lot of spells, but it's not like those spells are any great invention on the part of AD&D. Some examples:
(73) The Shutfast Charm in MYTHUS MAGICK (page 35) is derived from the Wizard Lock Spell in the AD&D 1st ed. PHB (page 72) and the AD&D OA (page 81).
(67) The Disembodied Voice Formula in MYTHUS MAGICK (page 34) is derived from the Magic Mouth Spell in the AD&D 1st ed. PHB (pages 71 and 96).
(114) The Circe's Transformation Spell in MYTHUS MAGICK (page 56) is derived from the Polymorph Other Spell in the D&D 1st ed. PHB (page 78) and the AD&D OA (page 86).
(81) The Understanding of Ur Spell in MYTHUS MAGICK (page 36) is derived from the Comprehend Languages Spell in the AD&D 1st ed. PHB (page 65) and the AD&D OA (page 75).
And some of the other stuff they claimed...
(2) The Heroic Persona Attractiveness rules in MYTHUS (pages 18, 102 and 391) are derived from the Comeliness rules in the AD&D UA (pages 6-7); TSR's DRAGON Magazine, issue #67 (pages 61-62); and the WORLD OF GREYHAWK boxed set's Glossography (pages 33-34).
(4) The concept of adjusting a character's abilities corresponding to its age found in MYTHUS (pages 104-105) is derived from the similar concept in the AD&D 1st ed. DMG (page 13).
(7) The MYTHUS concept of character vocations in MYTHUS (pages 13 and 70-71) is derived from the character class concept in the AD&D 1st ed. PHB (pages 18-33); the AD&D 1st ed. DMG (pages 16-21); and the AD&D UA (pages 12-25 and 74-75).
(8) In MYTHUS (page 67), the concept of and the method by which the game characters' attributes are defined by randomly-generated numbers, and the players' choices of vocations precede and alter such attribute generation, are derived from a similar concept and method in the AD&D 1st ed. DMG (pages 11-12) and the AD&D UA (page 74).
(30) The "Accomplishment Point" system in MYTHUS (pages 29, 40, 134-136 and 303-304) is derived from the "Experience Point" system in the AD&D 1st ed. DMG (pages 84-86 and 228) and the AD&D 1st ed. PHB (pages 106-107).
(32) The method used in MYTHUS (page 9) of resolving game action by generating random numbers on a linear probability scale is derived from a similar method used in the AD&D game system in the AD&D 1st ed. DMG (pages 9-10).
(33) The method used in MYTHUS (pages 9 and 236-238) of determining game character damage using a weighted probability scale is derived from a similar method in the AD&D game system in the AD&D 1st ed. DMG (pages 9-10); the AD&D 1st ed. PHB (page 37); and the AD&D UA (page 26).
(47) The name of the main world, "Aerth", in MYTHUS (pages 5 and 7-8), is derived from the name of a world, "Oerth," in the AD&D WORLD OF GREYHAWK boxed set, specifically in the Glossography (page 2) and Guide (page 4).
(48) The races of other-world elves called the Elves, Fay and Faeries, from the fantasy world known as Phaeree in MYTHUS (pages 332-333), are derived from a race of other-world elves called the "Pharisees" in the AD&D QUEEN OF THE SPIDERS game module (pages 107-108) and the AD&D QUEEN OF THE DEMONWEB PITS game module (pages 13-14).
So yeah, that lawsuit was utter BS.
(There really ought to be the equivalent of Anti-SLAPP statutes regarding copyright and other IP, so that if someone tries to bully someone else with bogus copyright claims they should at the very least be liable for the other party's costs, and pay a hefty fine on top of that as well. Or maybe lose the rights to the thing they falsely claimed was infringed.)