If you are talking about scripting, then I think you've failed to entirely understand the point. That is that the data specified as input to any script can't be prevented from being taken from another script by the external entity that provided that "transaction" as you call it.
That is exactly the point, though - if the external entity is required to specify the dependencies explicitly, the system ought to be able to reach an appropriate ordering.
If you want to talk about total eventual ordering of transactions for directed acyclic graphs, I think we should do so in
your thread.
I wasn't driving at discussing that, it just naturally appeared as a direct consequence of looking at your problem statement for ethereum.