I still favor Brazil for the trophy. but when it comes to dark horses, Senegal and Serbia will make it difficult for the seeded nations. Senegal will be in the opener against a strong Dutch team. we'll see how it plays out.
Brazil is a pretty solid team in terms of performance in their qualification to become the leader of the Zona Commebol qualifying standings, and have a good record and even won their last 17 matches they played so it's quite clear they have a big chance to be strong candidates for this world Cup.
As for Senegal, this is also quite interesting because they came apart from being underdogs, they are also AFCON champions, whose strength is beyond doubt.