Hitmonlee--
You can count Powell out, because he can't deliver when it counts--but both Johnson and Bolt can, and did.
As far as the start is concerned, I can do both Powell's and Johnson's starts--and all things considered, Johnson's has a greater potential.
Nobody could approach that potential unless they were hugely drugged, however, like Johnson was. For a normal athlete who has even a minimal chance of being clean, like Powell, Powell's start will be faster.
The start relates not only to the power that can be applied at the start, but the manner of the entire drive phase and transition and full-speed form.
If a guy like Powell tried Johnson's start, his 100m time would be slower.
As it is, I think that Powell and Johnson are probably equally quick over, say, the first 30m--however, Johnson could have been better. He showed no slowing of his improvement. He went from 9.83 to 9.79 (really 9.77, say), in a year, and had good years remaining in front of him, whereas we have already seen the best that Powell has to offer.
By some numbers, using Powell's 9.77 from Zurich, here are the splits for the first 3 ten-meter segments, excluding RT:
Johnson Powell
0-10m 1.70 1.72
10-20m 1.04 1.02
20-30m 0.89 0.92
By this comparison, to 30m, Johnson is quicker to 10m by .02, it is even at 20m, but by 30m Johnson surges ahead by .03
Also, RT cannot be discounted from the start. Johnson was great at RT, he was on a hair-trigger. Using these 2 races for comparison:
Johnson Powell
RT 0.132 0.148
So Johnson is ahead by about another .02
When that is added to the above splits, Johnson is quicker to 10m by .04, quicker to 20m by .02, and quicker to 30m by .05
Powell's Zurich 9.77 may not be the best start he ever got, but the same could be said for Johnson's 9.79 (for instance, in Johnson's 9.83 in Rome, his 10-20m split was 1.00, which is .04 faster than in Seoul)--it's just that data were readily available for the comparison.
Of course, all this split data is generally garbage, but whatever, it is all we have available, not being able to see the 2 athletes in the same race.
As far as reaching 60m outdoors quicker than the 60m indoor WR, that happens regularly, not just with Bolt.
As far as Bolt's stride goes, other guys have also had huge strides, especially compared to Ben's--Carl, for example. Bolt's stride is slightly greater than even Carl's, as Bolt had 41 in the 9.58, whereas Carl had 43 in his 9.86 However, look at this link, and you will see stride length listed, along with stride frequency, for Johnson in his 9.79
http://myweb.lmu.edu/jmureika/track/splits/Seoul.html
Johnson's stride length averaged over the entire 100m was only 2.15m whereas Bolt's was a huge 2.44m, but Johnson's stride frequency averaged over the entirety of the 100m was an incredible 4.76, compared to Bolt's 4.28
No doubt Bolt is incredible, but so was Johnson--in particular, with the amount of force that Johnson was applying to the track back then, his time to 40m would be significantly reduced today with the better spikes and better track surfaces available, especially the better tracks, and that decreased time to 40m would be due to a greater average stride length over that first 40m.
Just having Ben run through the finish and lean, and have his 10-20 from Rome instead of hsi 10-20 from Seoul would give him 9.72--and that is demonstrated capability, not accounting for improvements in equipment and/or doping.
Yet, that was still with some wind, +1.1 to be precise, so he would need to make up substantial ground due to track and equipment improvements to be even with Bolt.
I think he could possibly have done it.
Of course, who knows how a head-to-head race would develop. I would also like to have seen Johnson's response to slightly different coaching--that guy didn't run 9.79 on great coaching, he ran it on roids, with an M.D. as his primary coach.