You know, I've never had problems with the parkour, once you understand it's very simple principle: You want to grab/climb/mantle something, you need to have it roughly in the middle of the camera (which is explained at the start of the game). I've played some 16 hours or so and the parkour system fucked up only ONCE (and considering parkour is your only means of getting around, I'd say that's a pretty impressive track record).
Heck, the parkour is so much fun and feels so natural it's probably what kept me playing for so long.
And it actually improves on some of the best parts of Dead Island (melee combat is better, crafting is better, killing zombies feels much better, skill trees are really good), while getting rid of some of the weaker aspects of Dead Island. Mostly the game is about avoiding zombies rather than fighting them (though you'll still fight plenty). Writing is not great, and the voice acting ranges from ok-ish to terrible, though the main story is pretty decent, if indeed extremely cliched. As for the multicultural setting, I really like the simple and clever solution: the city was hosting the Olympics - that's why you have people with 50 different accents, and a lot of really fit, really athletic survivors.