As seen in the videos, I had no problem running either of my preamps "flat" into the cab - it actually felt like very familiar territory to me. More similar than different to my own 15/8 cabs (I'll leave it at that, don't want to de-rail this thread).
FWIW, I've always personally disliked the standard 410 + tweeter configuration due to the huge hole in upper mid response, so I progressed to other cabs that sounded more balanced, but I can see where folks that really like that profile might not dig something like this. For me, the mid response isn't much of a departure from a lot of the other stuff in my stable other than added clarity and cleanliness.
Problems with huge low end, assuming you have a properly designed cab (which these are), and not a huge low mid hump, stem from the amp (and possibly improper use of onboard EQ). Amp designers IMO need to spend more time voicing their stuff to keep the mud out - it takes time to balance a circuit to sound big without getting bloated downstairs. It's easy to let a huge amount of low end through the circuit, and likely sounds impressive and low volumes, but things get messy really quick when you hit the gas pedal, let alone if you get anywhere near the levels I like to slam. That's not the cab's fault.
Other than rolling with a sealed design to balance out the damping on a tube amp, the ball is in the amp designers court to get the voicing right, and a lot of them don't.
Active instrument EQ should be used sparingly (actually I think it should be outlawed along with tweeters, but thats a different story
) That's where I hear all the "gank" coming from. I sound pretty ganky playing on a Stingray due to my technique (or lack of), but I know guys who have the right touch and sound glorious. BUT, I hear even more
guys that sound like I do, and as such really need to rethink their choice of instrument, or at least learn how to properly set it up.