A few thoughts:
Whether it is good science or not, the idea of tiny robots and molecular self-assembly was what generated a good deal of the early public and political interest in nano. Look at Drexler's 1992 testimony before a Senate subcommittee convened by then-Senator Albert Gore (D-TN). The role of public imagination in the formulation of public policy is a dimension well worth considering. See, for instance:
Howard E. McCurdy. Space and the American Imagination:. Washington, DC: Smithsonian Institution Press, 1997.
So, while I'm not losing sleep about the nanobots, I don't want to forget about them either.
Another point - while there is a great deal of claimsmaking about the interdisciplinary nature of nano - and these may be true - like a good (former) scientist, I still want to see the proof. The formation of MSE was a long and contested process and one which many metallurgists fought tooth and claw. Although I don't agree with everything she presents, for one perspective on this process, see:
Bernadette Bensaude-Vincent. "The construction of a discipline: Materials science in the United States." Historical Studies in the Physical and Biological Sciences 31, no. Part 2 (2001): 223-248.
Is anything like this happening with nano? Where are the turf wars?