(moving to the appropriate thread ...)
That's really not practical. Updating the scripts is rarely as simple as just downloading the latest version of the script. Since I wrote scribe, I know scribe has a pretty detailed update process, and by watching their output, I'm pretty sure other scripts do as well. So it can't be coded into amtm. Additionally, not every script accepts a command to update (scribe happens to, because it was originally written as a command-line tool), so scripts that didn't already support this would need to add it on.
And, inevitably, something would break, and AFAIK, none of us retain the ability to regress scripts to the previous version. The unintended consequences are too great. As a script writer, I would be very much against this idea.