Perhaps we can emulate MPC with node shuffling and secure enclaves. Fully homomorphic encryption could also be an alternative to MPC in the future. All of these technologies could also work together to provide a solution.
I think the problem with MPC and FHE is that they aren’t practical yet. Enclaves and shuffling may provide an interim solution.
I agree that somehow hiding canisters from node operators could be an essential part of security