Given that you don't say in practice what nut you are trying to crack, it is hard to judge whether Template::Toolkit is necessary or not. Although what is being achieved by Class::Phrasebook seems to me on the other hand to be a bit underwhelming by comparison. One could argue that rummaging around a McDonalds kitchen is unlikely to get you a portion of foie gras de canard.

However, Template::Toolkit is often hard to get started with and it is indeed the need for its sheer power that tends to justify the effort.