That design would have made ordered dict incompatible with dict (an ordered dict couldn't be constructed with an ordered key, same for an unordered dict), and at the time, keyword args were unordered, so an ordered dict had to be constructed with an iterable of tuples instead of key value pairs.
I disagree. There’s a strange precedent for builtins overloading like ‘type’. The same could be done for ‘dict’. Do you want me to share a satisficing call signature?