Yes, ouch -- but this is actually a symptom of a more fundamental issue, which will take a larger refactoring to change.  Since we have to pull the dim_data dictionaries from the LocalArrays, we're getting all the indices as well.  We have to assume that this isn't possible, since it may not be possible to pull everything onto one process like that.

Part of the refactoring of the dim_data creation stuff is to fix things like this, and keep the client-side and engine-side maps separate.