"A decision was made"
Who made the decision? Yes, it absolutely can be more clear.
It is odd how all of his statements are in the passive voice rather than the active. "A decision was made to" rather than "X decided to". Does he always speak/write like that and I just never noticed or is he just being super vague about this whole situation?
Honestly, I just think he's being respectful of the band and the process of the band making the change. I think, as he told Mistress Carrie, that he understands what happened.
For better or worse, Trunk is probably going to be more interested in the behind-the-scenes of what happened than most other interviewers Mangini is likely to talk to.
Trunk is quite familiar with all of the parties, so I think Trunk is the perfect guy to do this interview. He usually asks the things that fans want to hear.
All that being said, that podcast that got posted here earlier makes me think that there was some paperwork signed about what Mangini can and can't say re: Dream Theater. He is clearly choosing his words carefully with phrases like "a decision was made" and even the way the interviewer phrased the question is a bit of a tell. She never said anything about Mangini being fired or quitting or even using phrases like "left the band." Just a vague "Mike Portnoy is back in the band that you were in." Trunk will probably be under similar restrictions to what he is able to ask.
I think the only direction given to any interviewer is that Mike will make it clear that he is not there to bad mouth the band, and that he also doesn't want the interviewer to do it either. There's probably details about when the band talked to him, the personal conversations, and some settlement language that will remain confidential, but truly, this has to be the least mysterious band splitting with a member that I can recall.
It all seems typical to how Petrucci has managed the band's PR over the years. Keep it vague and don't say anything that would cause a controversy with the fans. Plus the split with Portnoy got so ugly that they probably don't want to experience that again, even if Mangini handles everything with more class than Portnoy did they might not want to take the chance. I don't know how the legalities work but I guess there is also a more distant possibility that Mangini's exit package is still being negotiated (supported by the common speculation that this was announced earlier than intended to avoid a leak).
I said when it happened that the press release was probably the most honest and least vague communication ever put out in the JP run era.
They may have jumped the announcement up, but I would highly doubt that the ink was not dry.