Perl should drop sigils entirely.

No! The conveniences of having sigils surely outweigh the inconveniences (whatever they are). Although, I know naught of other languages so I cannot give a convincing argument to why things should or should not change. I can, however, say that the current way works great for me :D

That would do a lot to convince the rest of the programming world that Perl is, or even could be, relevant.

I think I am confused about the word 'relevant' in this discussion. Relevant to what?