One of the reasons we wanted to originally use Contant based addressing and short hashes as our threading model was to keep individual Twts short so that they were still readable if you viewed the manually by hand.

With the proposal to switch to location based addressing using a pointer to a feed and a timestamp in that feed you’re looking at roughly 2025 characters long because both the HTTP and HTML and even URI specifications do not specify maximum length for URI(s) AFAIK only recommendations.