You can not simulate or test the social and economy impact of 8MB blocks in the test net, that's the key difficulty
No one can see the future of a complex decentralized social and economy system, the safest way is to make the change as small as possible, one small step at a time
I do like that idea, however that means we would have to hard fork on a regular basis. I do not think that this is practical or even possible without splitting Bitcoin, especially as more people become involved, it will become even more difficult to reach consensus. It would be better if we do not have to debate this again in a few years from now.
This is a great example of something that makes perfect sense technically, which however might not be as practical or feasible from a political perspective.