The second parameter of the `createrawtransaction` is a dictionary of the outputs. This comes with at least two drawbacks:

* In case of duplicate keys, either of them might silently disappear, with no user feedback at all. A user needs to make other mistakes, but this could eventually lead to abnormal tx fees.
* A dictionary does not guarantee that keys are sorted. Again, a user needs to keep this in mind, as it could eventually lead to excessive tx fees.

Even though my scenario of loss-of-funds is unlikely to happen, I see it as a inconvenience that should be fixed.