There's a difference between Josh Barnett and Jon Jones though. He'd get worked on the feet with Jones. His reach advantage will be too much to overcome. The only thing that we don't know is how dropping to 205 will affect his ability to take down Jones.
Jones doesn't have the jiu jitsu to submit DC if he gets taken down
Jones doesn't have the wrestling to stop DC's takedowns
Jones doesn't have the knock out power to knock DC out
All Jones has is his reach and I have a hard time believing Jones is gonna beable to keep the f!ght standing by just using his reach. Once they clinch up it's game over for Jones. Mir couldn't even keep DC against the cage for 10 seconds befor DC reversed it.
This f!ght, DC didn't take Mir down for whatever reason, maybe he was scared he would get submitted. In the Barnett f!ght, DC threw Barnett around the cage and had cardio to go the whole f!ght because it wasn't a clinch fest like this one was. The clinch is incredibly grueling, it tires your whole body out. DC had to force and hold a 260+ pound Frank Mir against the cage for 15 minutes against Frank's will. That is going to be very taxing on your cardio no matter what.