As I pointed out in my last post, the use of the OGL to publish a game, even a game based on prior editions of D&D, is not required. Such a game could, like Gods & Monsters, be published on the basis that game rules can’t be copyrighted.
Legal cover. It’s a smarmy reason, but I can’t help but feel that publishing under the auspices of the OGL will make WotC more hesitant to take legal action against a company that is publishing material based on their intellectual property. While such a suit might ultimately lose in court, I confess that Hasbro’s pockets are just a teensy bit deeper than my own. While I love how Adventures Dark and Deep™ is shaping up, and I think a lot of other people are going to be pleased with it as well, it’s not worth my house.
Third Party Support. 3rd party publishers are more likely to publish modules, settings, etc. for Adventures Dark and Deep™ if they have that aforementioned legal cover. While this is, at best, a tertiary reason in my own mind, it’s still something to consider.
Ummm… anything I’m forgetting?
Identification of compatibility. By using the OGL, I would forever ban myself from being able to say “compatible with Advanced Dungeons and Dragons”, and that I think would be a shame, given that Adventures Dark and Deep™ is going to be extremely compatible with AD&D, and I might sell a few more copies if that is made obvious (frankly I would be happy if the only copy I ever sold was to myself, but it’s something I do need to think about). I could, in theory, make such compatibility known in promotional materials, as long as those materials themselves aren’t OGL documents, but I would still prefer to have the statement right on the products themselves, if possible.
Use of forbidden creatures. By publishing under the doctrine of “game rules can’t be copyrighted”, I become free to use creatures such as the mind flayer, carrion crawler, displacer beast, etc. And I like those creatures.
Again… I feel like I’m forgetting something, but I can’t seem to think of what it might be.
UPDATE: I am reminded that OSRIC does indeed use the OGL.