Frivolity aside, I really wish this issue would get more traction and a fix.

Indentation is an important part of the Python language (obviously).  A pretty standard way to indent is to hit "tab" in whatever environment you're using to edit Python code.

Yet, at the interactive prompt, tab doesn't actually indent on a blank line. Instead, it autocompletes the builtins.  Aside from it being highly annoying (as previously mentioned), it is also an embarrassment.

Newcomers to Python will very often try things out using the stock interpreter before moving on to more sophisticated environments.  The fact that tab is broken from the get-go leaves a pretty sour impression when not even the most basic tutorial examples work at the interactive console (and keep in mind that whitespace sensitivity is probably already an issue on their minds).

Experienced Python users coming from Python 2 to Python 3 are going to find that tab is busted in Python 3.  Well, of course it's busted because everything is busted in Python 3.  "Wow, this really sucks as bad as everyone says" they'll say. 

So, with that as context, I'm really hoping I don't have to watch people use a busted tab key for another entire release cycle of Python 3 as I did for Python-3.4. 

I have no particular thoughts about the specifics (tabs vs. spaces) or the amount of indentation.   It's the autocomplete on empty line that's the issue.