from the moment the data is not transaction, and doesnt relate to previous state, the whole block validation process become meaning less, as well as most of double spending related issues. And it remove lot of the issue to incencitive block emitters.
Absolutely agreed on this point, though I think if we really abstract away the application from the content data, we have no way of knowing the transaction is valid or not. If I'm not running BitUber, how would my client determine if the BitUber transactions are valid.
Also in my opinion, you are fundamentally responsible for being your own block emitter. If you want to spend a cryptocurrency you obtained, and your blocks have not propagated enough you may need to provide the store with a large packet containing all the blocks/chains necessary to fully trace the inputs to your transaction for validation.
Nothing is stopping someone from someone having many chains, one for crypto-currency (keep it small) and another for content (Large!).
Thank you for your input. I look forward to hearing your design.