I think you're overanalyzing it, Bass. I'm not sure about Waid's particular views, but I'd surely like to see a DD series. Granted, it'd explore more "adult" themes through both the legal drama court room proceedings and the street level crime and violence, but I don't think it's necessary or even right to alter the concept and foundations of the source material to make it "gritty" or "dark" (there's enough of that already in DD). I also like the idea of combining established genres (legal, police procedural, and super-heroes/vigilantes) into an hour long weekly series, as long as it comes off well.
Personally I think a DD show related to the MCU movies would be great fun, and possibly serve as an avenue to introducing other Marvel street-level characters like Punisher, Blade, Luke Cage, Iron Fist, Misty Knight, etc. On an occasional basis, mind you, as this should be a DD show first and foremost, not Marvel Team-Up labeled as DD. It'd also be a great testing ground for Marvel Studios to gauge the fan interest in these characters and their viability for possible MCU films of their own.
I'm not a writer, producer, or showrunner and only moderately familiar with DD and his supporting characters, so I can't necessarily pin down a specific approach on the tone, approach, or direction it should take. I think part of my problem is I'm viewing it as a theoretical cog in the MCU machine instead of viewing it strictly as it's own animal which may or may not fit into the bigger picture.
In terms of co-opting it, I get your point, and agree artistic merit should come first, but as a realist I also recognize that studios are trying to approach and hook as large an audience as possible. If that means giving in to the more cynical, less intelligent approaches to telling these stories in an attempt to get that larger audience, it's a shame but I understand it.
I disagree with your summation that making "superhero" books more adult is intellectually bankrupt, though. I hate to drink from the Watchmen or Miracleman well once again, but I'd argue those are the best examples of superhero books aimed at older readers who took a somewhat more realistic, deconstructionist approach and succeeded beyond measure. Granted, just about every writer since has tried and failed to reach those same heights of comic genius, but I don't think pigeon-holing and specifically labeling different books into rigid genres and sub-genres is the way to go (including their various adaptations). Inevitably that'll stagnate creativity, imagination, and original story-telling, just as less talented writers trying to ape Moore has done. Same result, different avenues.