My overall predictions:
1) Junior Champion is going to be playing a donk deck. I'd say Machamp, simply because it is simple enough for a kid to learn. Give a monkey a donk deck and it could take Juniors.
2) I have to say that I see Aylam taking Seniors at Worlds. I know it may be a bit of an overestimation, but I have to say that this kid knows what he is doing. I know that Aylam will be playing some form of Gengar, I am thinking it is going to end up being Mother Gengar.
3) Masters (where it counts) I'm seeing either Luxray or Gengar. Personally I'd prefer to see Luxray, but in all seriousness I would say Gengar will probably end up winning. I doubt that the Luxray will be playing Infernape, as most players are starting to realize that the Infernape was mainly just a bad idea when compared to things like Manectric, Toxicroak (not so much), and Palkia.