You can only guarantee it goes the distance but will be debatable. Johnson has such an annoying style. He doesn't really defend, he just rolls with punches. He throws at such a high volume but never with any meat on his shots. He plods slowly but cuts the ring off well. What does this guarantee? He'll get hit an awful lot and land an awful lot. So the fight will always be debatable. You can watch every fight he ever had at LHW and make a decent argument he won them all.
Would be a fun fight to watch and probably similar to the Johnson vs Cloud fight that I saw live. I do see similarities in Cloud and Barkley. Both were tough two fisted bangers that were limited defensively. Johnson was not as heavy handed but was tough as nails and pretty danm solid all around. I lean towards a prime Barkley by decision but honestly wouldn't be surprised if it went the other way. Would have loved to have seen it.