I'm more upset with Mark's lack of clean tone. It literally makes songs with those classic Tremonti cleans sound bad when he tries to just roll his gain channel back. That's something that is easily fixed, just use the clean channel on your amp.
It often isn't. Both the Bogner Uberschall and the PRS MT15 are high gain amps. In order to get the amount of gain that Mark uses those amps are designed to distort and increase distorting as much as they can. If Mark is also using high output pickups, there might not be enough clean headroom at the desired volumes to get as clean a sound. This is why Mark used to tour with Fender amps as well as Mesa Boogie, and why most high profile touring artists use multiple amps. I have this issue with my Hughes and Kettner Tubemeister. The clean channel is great with single coils, but introduce high output pickups like those in a 90's Les Paul and it doesn't stay clean very long.
The problem is he has no excuse as to why he wouldn't bring a Fender as well. They're available to rent everywhere, their production value is higher than ever and he still brings so many 4x12s he could easily drop one and replace it with a Fender Twin and have no big increase in freightage. ESPECIALLY in a show like this where they're almost focusing on the cleaner, softer songs. Doing Festivals where you play your heavy rock singles or the smaller venue Tremonti tours, sure, why not. But this is a special occasion where you want everything to sound as good as it possibly can.