Open dynamic headphones tend to have no sub bass. Please give me ONE dynamic headphone that doesn't roll off in the sub bass. So, you're basically complaining about a dynamic driver's NORMAL shortcoming, not limited to the MA900. If you expected sub bass from a headphone THIS open where there is a GAPING void between the pads and the drivers...well, you don't understand the laws of dynamic drivers amd their limitations. That's your own fault. Go get planars that are able to push vasts amounts of air enough to keep the sub bass intact.
Fatigue? The linearity in midbass all the way to the upper mids makes them ideal for multipurpose use. The roll off in the treble is a flavor that is also not limited to the MA900. Plenty of headphones with that roll off, including some heavy hitters. That is also not a problem with the MA900. It was tuned to be that way, and is a preference thing, not a shortcoming.
So yeah. bad headphone for days. Right.
And actually I greatly prefer the MA900 to all the AKGs other than the Annies which are double the price. You talk about fatigue, when the K701 was dry, analytical, and had a pesky upper mids peak that stuck out like a bad pimple. The K702 and Q701 fared better, but they still lacked body and warmth for my taste.The MA900 is warmer than all the AKGs other than the Annies, and more musical to me. So no. I like my MA900 more for all purposes, other than the Annies being superior, but not as comfy.
Then you're comparing a headphone that first retailed at $300, and sells for $200 or less normally, while the AKGs retailed for nearly double that, and are only in the $250 range now due to how long they've been around. Not to mention the MA900 sounds more or less the same off anything, while the AKGs need considerabke amping to sound up to spec. You're comparing headphones in two distinctly different price ranges and requirements.