Jurgens actually gets the no. 2 ranking. He introduced the antimatter, gave us great new villains with The Dark Gods and Desak and showed Thor as a capable fighter. His Odin was a bit underpowered for my taste and The Reigning left a bad taste in my mouth; mainly for going on for too long.
Its almost unfair that a guy who wrote only 6 issues on the main title gets the no. 1 ranking but lets face it, the Rune Thor storyline was the best thing since Walt.
Probably the guy I found the most disappointing but he still ranks no. 4. Great ideas but mediocre execution and some of the stories were so boring, my eyeballs damn near bled reading his cure for insomnia stories. I loved the Ironman fight and the Bor fight which shows the guy does know how to write a fight when the mood hits him.
I love just about everything Gillen writes regarding Thor. I don't think I'm alone in wishing he was the writer on the main book. He cleaned up JMS storyline very effectively which is a hard thing to do, coming in midstory and taking over. The only reason Jurgens ranks ahead of him is Jurgens had longevitky on his side and I liked Jurgens work up until The Reigning.
NO. 6 He actually reminds me of Fraction in he comes up with a pretty good concept and doesn't seem to have a clue how to write a middle much less and ending to a story. He's ranked last because of the current godawful Thor Deviants story he's currently butchering.
No 5 His work on Thor has pretty much been a bucket of shit thus far. This guy can't script a fight to save his life. I've waited almost 40 years to see an Odin vs Galactus fight and this guy gives us a freaking headbutt. Fraction also can't quite figure out how to introduce new characters and make us care. Think about the Dark Gods, Perrikus was instantly seen as a dark mirror image of Thor and MajestriX Zelia a dark Odin. I don't think Fraction even bothered to give the World Eaters names. His tenure on Thor will be remembers as a failure IMHO.
They are just so forgettable and nothing ever set them apart we do not remember them.