I am not convinced that Jon Jones is a tougher fight than Anderson Silva. While Jones is physically larger than Silva, he has neither the speed, accuracy, and.....power that Silva has, and it may be possible to survive a mistake against Jones that would render you unconscious against Silva.
My recollection of the last Silva fight was that an emaciated Sonnen, although not damaging Silva, dominated the first round. Tactically his approach was sound and applicable to Jones. Not having to endure the weight cut may be a huge benefit. Those of you expecting a knock out may be disappointed. People are forgetting that Sonnen is a world class wrestler, and as long as Sonnen can overcome whatever mental issues he has with respect to winning, he may, in fact, shock the world.