I just wanted to follow up by mentioning that I have now read the entire Perl5-Porters thread, and am surprised at how well received this is. There are a few dissenters, but a lot of "hey, neat" sentiment.
My opinion remains the same, if it doesn't make impossible things possible, or hard things easy, it isn't worth the added complexity, confusion, and certain need for debugging that would be levied on the poor user base. But perhaps it does beg a different discussion; the proposed change requires a patch to the Perl code base. Rather than patch to make this change, patch to make it easier to implement such a change without modifying Perl itself. In other words, make it possible for mortals to create a "dots" pragma without each such pragma requiring a change to the Perl core. That would be a more generalized and more useful solution, and while it would still be adding complexity and a round of debugging, it would at least be giving the users the tools rather than the widget made by the tools. We know exactly how a "dots" pragma would be used (if at all). Its advantages seem only to shave a few keystrokes. What benefits a language more is those features that are general enough that we cannot predict all use cases.
If hooks were implemented in Perl's code base to allow a "dots" pragma to be created without recompiling Perl, the pragma could be placed on CPAN rather than as part of the Perl core. CPAN is really where something like this belongs. And someone might actually find a way to use those hooks that is more meaningful than just re-purposing dot, and eliminating ->.