Well, democracy in Tunisia imploded and exploded. So, yeah, be careful of things that look good on paper.
In any case, Tunisia is not the only country with PR. It's used a lot of places, including Germany (well, MMP, but pretty similar). Like any system it has advantages and disadvantages, but democracy in the Nordics hasn't imploded nor exploded...
It's different, I think. Germany offered help (along with the EU) and Tunisia(ans) don't know any better so they took up the offer. Plus it was free help and free money. I don't think Germany or the EU had any malicious intentions, I think they truly wanted to help.
But big surprise: Tunisia is not a Nordic country! Apparently, what works there doesn't work here at all.