That definately looks like a Teila problem (i.e. Blizzard's ISP) m8, everything up to that point looks like it's stable 90ms which is decent latency. It's quite nice to see the difference between our tracerts though, yours is clearly pointing to an issue at hop 10 whereas mine is from hop 2 onwards indicating a more local problem, that's why I haven't bothered sending a tracert to Blizzard myself.
This now a known issue by Blizzard as of yesterday. There is a thread in the tech support forums asking users to post with using a template set. It appears alot of users from all over Europe are having the same problem, some of those having this Telia issue we're having. I knew the server was in Sweden but I didn't know it was Blizzard owned. http://forums.wow-europe.com/thread.html?topicId=6986529557&postId=69859618656&sid=1#13 Probably best to post your data there, I think we can stop bothering the plusnet staff now as it clearly nothing wrong on their behalf and bother blizzard instead