Kickstarter. Make the features on that level be stretch goals.
A kickstarter that gets millions of dollars gets you something like Pillars of Eternity.
Witcher 3 the developer took a long time to get those resources to do it (20 odd years).
That is my main argument they need a hit game 1st to build on because people are not risking tens of millions of dollars on new franchises.
And I think people over rate the value and appeal of the D&D brand in video games. They have not had a great one since 2000.
If they can sell 1 million units at $20 a pop and spend 1 million making it steam takes their cut but you would still have 14 million dollars left over with change. The sequel costs a bit more to make and maybe you kickstarter 4 or 5 million.
Witcher 3 done by a Polish company. 81 million dollars.
http://www.gamespot.com/articles/this-is-how-much-the-witcher-3-cost-to-make/1100-6430409/
To fund a game at that level (which is not even that expensive these days) you need a franchise behind it or a game studio. That is around 2 or 3 years revenue (not profit) of some of D&D's best years.
You're not gonna be able to crowd source 80 million dollars.
There is a reason there are less games being developed for PS4/XboxOne these days than say PS2/3 and the Xbox360. Production values have gone nuts and the games are not really selling that much more on average or even less due to smaller user bases.
You also need a certain amount of passion. so if you can get 20+ programmers who appreciate D&D with tens of millions of dollars available go for it.
You're not going to get a Mass Effect/WitcherIII/Dragon Age quality game with D&D on it any time soon.
Older article. Stardew Valley tops 1 million in sales.
http://www.polygon.com/2016/4/13/11423844/stardew-valley-sales-one-million-copies
That is a few more than Legends of the Sword Coast and its only on Steam, the game is available on PlayStation Plus and Xbox store.
1 developer, 1 million+ in sales.
Witcher 3 81 million dollars, 1500 people involved.