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I would do the following: Redirect every URL from the old site to the appropriate page on the new site. Rewrite any content that is below standards prior to moving it over to the new site. The old idea of having more pages meaning more internal pagerank, etc.. went out the window years ago with the Panda update.

It depends on a lot of factors, but in general, I don't like to put category subdirectories in unless they are necessary. For example, if a category page is useful to your audience, then it might be a good idea, but in this case it doesn't sound like one would be. Also, consider how your audience will react to the URL: domain.com/attorneys looks a lot better to people, I think, than domain.com/industries/attorneys, which implies you're marketing to a bunch of different industries and may lead them to believe this is solely a marketing play and you don't actually understand their needs. A page right off the root seems more exclusive and like you care more about their industry. These are just my opinions. From a strictly SEO perspective, you're fine either way, but I'd still go right off the root.

A different thought here. Since you are doing printing as the service, would some things (especially business cards) be able to give a good clue as to industry without having to ask people?