Currently, the Splinterlands codebase is proprietary and is owned, along with the Splinterlands IP, by the Splinterlands company, so it will only be possible to hire a third party to develop any of these things with the company's approval. That said, if the community finds someone who would be able to do this and approves that, we would be happy to explore it and see if it makes sense. Our only goal is to build the best product for our players and to grow the ecosystem as much as possible, and I am open to any better ways in which we can accomplish that.
I would keep in mind, however, that I don't expect this will be as easy as you think. For one thing, I'm not sure many other companies would be willing to be paid in DEC tokens, or if they were that they wouldn't just dump all of them on the market which would be a huge negative for SPS stakeholders. That being said, if you would like to put out an RFP then go ahead. It's up to the SPS stakeholder community how they want to proceed with this, we are simply putting out our proposal for the community to consider.
From the proposal's scope, it is developing the cards. There is nothing about programming and implementing them
In the first paragraph it says: "The company is asking for 600M DEC tokens paid upfront upon the approval of this proposal to cover the development, release, and operation costs of the set..."
So the proposal price includes creating the cards, abilities, and any new mechanics, testing and balancing them, implementing them in the game software including the updated conflicts and new pack types, and then releasing them and operating the game with the new set included.