Good article. You make some good points. I think the biggest concerns are the longevity of the image, and the ability of a computer to withstand the rigors of the field.
The research project I worked for in the mid nineties was checking the viability of digital cameras in the field as a means to aid in three dimentional computer reconstructions of sites. They destroyed three cameras in one summer. The Pentax and 50 mm lens that looked like it went through a war had lasted for ten field seasons and showed no sign of wearing out. I am sure the quality of the cameras have improved but the ccd issue you raise has got to be a big issue. For instant feed back they were great. We could take images of strata and evaluate them that night against the maps we had drawn.
Your concerns with longevity and readability of the files in the future, you would think, would make many weary of moving to the digital format entirely.