My issue with MM isn't so much his style or his technique, it's the recordings themselves, which isn't necessarily his fault.
But the biggest issue I've had with Mangini-era DT is that a lot of the compositions sound like they were created BECAUSE MM is so technically proficient, but just because you can play something with incredibly odd timing or throw in these extra notes or bars to a section, doesn't mean it's going to flow well, or sound good. I noticed this type of thing started happening on BC&SL, so it isn't just because MM is behind the kit, but MP would make those little parts flow better with his style. With MM, it sounds tighter, but still comes off as complexity for the sake of it, which does nothing for me, and I'm a musician.
So many examples in the last 4 albums, I can't think of one off the top of my head, but think of that short section in The Count of Tuscany that leads into the ambient section, where the arpeggio sounding part have that one extra count added in between each rep. MP makes it sound more natural, with MM, something like that they try to make it sound as insane as possible, but to my ears it sounds overly complex for the sake of it, and doesn't flow, as MP's style keeps a thread going underneath while all the complex stuff happens above, if that makes any sense.