An end user, for example an EU policy expert, looking at results calculated by a chain of models for different policy scenarios requires information about the uncertainty of the data. This uncertainty is some kind of "total" of the measurements and models used in the model chain. The uncertainty information is essential to the end user for evaluating the results.
How to address in Version 1
I don't think OpenMI 1.0 provides any mechanisms for indicating data uncertainty and how it affects the end results of linked models. Guess it is up to the person using the system to decide.
List all possible problems that you may expect in version 1.x of OpenMI.
How to address in Version 2
Present ideas in any form how you'd expect it to work in the OpenMI 2.0