Nick Heer has a few thoughts regarding the hoopla around tech podcasts of late. He also has a few suggestions for how a tech podcast, that he'd enjoy, should be structured:
By having a structure in place, rambling is reduced. A good editor can remove most off-topic talk and lag time, but having some sort of format creates a framework around which to build the content. They also help keep the podcast to a time limit.
I used to have a 90 mile commute to work. I burned through a lot of podcasts during that time. These days I listen to but a few podcasts on my incredibly short jaunt to Plain Space. However, I'm now on the lookout for a Mac app to subscribe to some podcasts to listen to while working.
I tend to agree with Heer's suggestions for tech podcasts though I'd really hate to see the structure get so rigid that the host begins to feel as though they need to push a topic off in order to move on. It is one reason I hate TV. TV hosts will begin discussing a really interesting topic and have to move on due to commercial breaks or segment switches.
I guess I'm saying, have a structure but be willing to throw it out.