The big question: Has the Ag Discovery Center been a success? I sure hope so, but an investment like that requires a lot of people walking through to pay for it.
I can't help but to think of "Roger and Me" , in which the city of Flint, Michigan built a big touristy auto tech center that utterly bombed, closing its doors within a year or so. If you build it, they may not come.
Indeed, The Land pavilion would be great with such a place. Many of us have brain-stormed big ideas for Epcot on these boards. Thinking them up is easy, implementing them is hard, but getting them past the bean-counters may be the hardest of all. Nowadays, Disney is worried that their can't miss ideas may indeed miss. They've had many bombs in the past, and those failures (or at least disappointments) have likely made them shy away from some of these bigger and better ideas. Movies like John Carter, attractions like Mission Space, and wienies like the Sorcerer's hat at Studios were expensive disappointments.
Personally, I probably do not want to see a cow giving birth on my vacation, but the combine thing could be awesome, especially if you could take some grain stalks, put them through the machine, grind the seeds into flour, and make a loaf of bread out of them. My kids would get a huge kick out of that. Yeah, the whole process might take a half hour or so and require a lot of CMs, but how cool!
We always enjoy the Livin' with the Land boat tour, mostly because it's a relaxing break. We especially like the domes part, with the unique plants. I assume this is the probably the last of the original attractions from Epcot Center that's still running. I like it, but I must admit that a park full of basically "ride around and look at stuff" attractions would not be very exciting. From what I hear, the original Epcot Center was a lot of that, and today's guests want more thrilling experiences. Innoventions they say was more hands-on, but thrillier attractions are what people expect today. And slapping an IP on it helps satisfy the bean counters that it will pay for itself.