It is coming out of a 20" dia pipe.
3.1415 * 10^2 * 3500 = ~550 tons of force, about the weight of a 200ft ship
Then throw in a gas/oil 2-phase fluid with different viscosities and varying temperature -- it is not an easy problem to solve
Some good technical info here: http://www.greendump.net/the-oil-drum/deepwater-oil-spill-th...
However sometimes when I watch the "oil cam" I secretly wish to see someone in some kind of DIY "iron man" deep-diving outfit suddenly appear and walk over to the pipe and start fixing it themselves, lol.
The pressure differential between the oil and the water is pretty low (20k barrels/day isn't that much for a pipe that large) so crimping wouldn't require much more energy than bending a pipe without any flow.
However, I don't know if there are ROV attachments that are strong enough and whether there was the required access.
The other problem is that a crimp probably won't result in a complete seal. I don't know if there was room for multiple crimps or their cumulative effect.
On the other hand, crimps would have reduced the flow while the relief well is being drilled.
The other problem with crimps is that they may make it impossible to do other things.
OTOH he doesn't have data on the exact pressures and forces involved, so BP probably had far better information on which to act. (and it's far easier to be an armchair engineer!)