I seriously don't know why people keep thinking it's a good idea for DF to get corporate money/support. Corporations care about calculating profit margins when making games because they are businesses and we pay Toady to make his game because he wants to make the same kind of game we all want to play. There is a difference. I will say that Blizzard and Valve are two of the companies that really stand out in not wringing the neck of the customer. The only games that get upgraded with a significant of continuing content so far are MMOs and the content they receive is further storyline but with Toady we receive new game mechanics that make the game deeper and deeper.
As far as I'm concerned, the things we love about DF would be compromised by bigger business and other minds and interests taking ownership in DF. Just about the only thing that wouldn't do that is if Toady were left a small fortune by someone and told to use it to make DF in any way he wants (which would just be a larger example of what we fans do on a regular basis)
There's nothing de facto wrong with commercial game design, it just doesn't always give the deepest most satisfying gaming experiences.
One other thing that might be cool is what if valve put DF on steam with no strings attached, just because they felt like it... meaning that it was free and it would basically just be another place you can download it. That would give it tons of free publicity.