OK, so I agree with you that the classloader approach is sub-optimal, but I also agree with Paul that it is the right first step to at least determine if WF can benefit from using ArjunaCore for the MSC. Assuming this proves to be the case, then any change to ArjunaCore to remove reliance on global state should be opaque to the MSC anyway, since you will be utilising it through interfaces which will not be changed by any subsequent modifications to ArjunaCore.