Earlier quoted context omitted.
We're not going to do that, for a bunch of reasons. One is that it's a creative constraint which (after 15 years I think we can say) is always possible to work within. Another is that if we made it longer, people would soon experience the new length as a constraint in its own right.
One trick is that HN also recommends we use the original headline from the piece posted. Whenever I have to edit it for length, I sometimes worry I'm going to be warned for editorializing a headline.
Editorializing has to do with changing the meaning of a title—for example to put a spin or interpretation on it that the submitter wants to emphasize. On HN, submitters don't get to use the title field as a sort of mini comment box.