If I had to guess, it'd be that Brother Orpheo took issue with some of GM Dave's "funny commentary."
And he wouldn't be alone. Dave's an opinionated individual, and really doesn't have much of a filter with some of what he says, particularly if he's gotten deep into his "wacky radio host" persona. He's likely ticked off a number of people over the years, who honestly don't listen to the show in spite of the informative material that's frequently presented, simply because of his antics. He has his personal prejudices and biases (we all do, so I don't fault him on that count), but they slip into the show more often than some folks would prefer, and he's entirely unapologetic about it; the few times when someone tried to point this out to GM Dave, he took it as personal insult and outright attack on him rather as possible criticism that could lead to improving the show. I made one such attempt, and got called out as directly attacking Dave; likely the only reason I didn't get banned from the boards was that the Lead Moderator (who does most of their work in maintaining the boards) was on my side in that particular incident, and the whole thing wound up getting brushed under the rug and the posts in question deleted by said Lead Moderator.
I still follow the podcast, having done so since the earliest days of when they were a Saga Edition podcast, as I find GM Chris to be both knowledgeable and entertaining without having to go overboard on the "wacky radio host" gimmick that Dave uses, plus the discussions with Jay Little and Sam Stewart have been extremely informative regarding this system. I updated by iTunes review from a 5-star (made prior to them winning an ENnie in 2009) down to a 3-star review, based upon GM Dave pretty much becoming a caricature and almost literally "phoning it in" regarding his behavior and interest in the material when I've heard evidence that he can do a hell of a lot better as the show's co-host. Sadly, it got drowned out by all the 5-star "We luv u guyz!" reviews and I've pretty much been written off as "the Russian judge" simply because I voiced some actual criticisms with the show. To be honest, I find the shows where Dave is replaced by a guest co-host, particularly GM Phil/DarthGM to be far more interesting, since I don't have to mentally filter out Dave's "wacky radio host" style remarks.
There are other podcasts (such as the Sabacc Table for instance) where the none of the hosts play the role of "uninformed pleb" that Dave sometimes adopts for the show in regards to the topic (he's far from uninformed regarding the subject material), done so as to be "funny," and that's something that not everyone appreciates. If one of the hosts of the Sabacc Table is uninformed about part of a topic, it's because they're legitimately uninformed as opposed to Dave's forced attempts at "playing dumb." Unfortunately, things are so entrenched that short of GM Dave stepping down permanently from co-hosting the Order 66 podcast, it won't change. It's their formula, and they're getting enough positive feedback to encourage to stick to formula even if it winds up alienating possible new listeners in the process.
/rant *steps down off soapbox and walks away*