It's not a "new" console which is coming out next year. It's just a revision. This fall, MS is switching from the Falcon mobo (80nm gpu/65nm cpu) to the Jasper (65nm cpu/gpu). Late next year they will switch to the Valhalla mobo, which would contain the cpu and gpu on the same die.
At launch, MS kept the selling price as low as possible by only including what was necessary to turn on the console and play. So I could understand not including wifi, amongst other things.
That was almost 3 years ago now. They are making a profit on each console sold. So I, too, feel they could at least intergrate the wifi in to the new revisions.