Hi Osorio,
I am also experimenting with polymer and pw. However, I deceided to modify the .htacess to allow html imports.
I don't know if there are any security drawbacks but I can't think of any.
In my opionion it's better to keep the templating files in the template folder where they belong by design.
Maybe ryan could clarify this because there were already 2 people in 2014 who asked the same question.