The only way to truly determine whether big blocks or reduced utility will kill bitcoin is to run the damned experiment.
But because bitcoin is the only meaningful cryptocurrency with enough serious traffic, you can only run the test on bitcoin live traffic...
yes...
which means you have to reach consensus first.
..aaaaand NO. Consensus is an emergent property of the system.
blah blah blah (paraphrased) [sorry - we're just talking past each other - ed]
Nope. As previously stated. Imma run 2 MiB. Try to stop me, mofo*. *ppttthhhbbbllttt!*
*no animosity expressed or implied XD