I understand the need for v7 before v8, to ease users with warnings so they have some time to "use v7" (and then an easy transition to v8). instead of v7 being what v8 intends.
Personally I think that a "use v5" or having a hashbang that points to perl5, where that is a link to the perl v7 or v8 binary, with the automatic behavior to enable old syntax is something that needs to be made, so that "old perl code, do not touch" just keeps working with a single change. (next to the "use $version" we have now, to develop for older/newer systems)
Having said that; I'm very hyped about the new Version number, I hope that just like PHP got a boost, Perl7 will get a boost too. As you can see, my love for Perl hasn't faded over time :)