Honestly @#$^ the license, and Intellectual property and the like. Leave setting, and development stuff alone(AKA to the Fellow/Lass who's putting it on for others).
Write up classes(Hint, use dragon age for a basis).
Write up major abilities(Hint, use dragon age for a basis).
Write up minor abilities(Hint, use dragon age for a basis).
No idea how DA does its hak, or equivalent, I picked up the 360 edition. But NWN has the right notion here..
Now, sell it in 3 flavors:
$30 Adventurer: MP client, and Toolset.
$45 Wizard: Adv +DM client.
$50 Deity: Adv +Wiz + stand alone server app.
The perks are simple, its an easy $30 write off to try it, and see if you like it. Don't like it? Did you get 4 hours out of it? 2 trips to the movie theater would run more than $30 where I live, so its an easy sell.
Next trick is you sell the upgrade to the next package as $20. So buying them individual one at a time(AKA, as you get more involved).. $70 Buy it all upfront you save 20. Buy intro, and then decide to buy it all fresh(I.E. passing your first purchase off to a friend) Net's $80.
Now.. let's talk continuing income.. Every 3 months, release a purchased game update, for $15-20. I would suggest, each dollar spent get's a new placeable, a new creature appearance, a new feat(Or just 1 new class per update to simplify it), and a new spell. That works out to $0.25 per piece of content the end user gets. Rough formula, but let's keep in mind, these things would be marketed free of charge for bioware.
By none other than the user base. I mean, the PW owner buy's ituses the new creatures in the next week or two, and thus, his players are in the position of needing to update. Now obviously, they could put it off if they chose, but we all know how fickle players can be right? Alternately, one of the staff of the Play world get's it, drafts up a new dungeon, with new stuff, and the Owner can't import it without upgrading.
Now I don't realistically know how much work would go into making 4 new things (per dollar * updating players). But my gut instinct tells me this is one hell of a marketable "Build your own MMO" kit, and Bioware has had 90% of it done for at least the past 4 years now.