I think a perfect placement for Perl would be as a second language to be taught in high schools. The first language can be something like Pascal or Java or whatever they teach in CS AP these days. I think the first language should be simple and there to teach programming principles.

I think however that advanced students are going to want to do real work as fast as possible and Perl is a terrific tool to have in your pocket. Hence, I'd teach the majority of students what they need to know to pass the AP and then the good ones, I'd put in a Perl class.