When you get in the cage with guys like Koschek, Alves, Condit, and even Hardy (who I suspect would have you running in no time) then it'll be time for you to question the testicles of someone who's gotten in the cage and had the door closed behind him many times.
My suspicion is that he just doesn't have the power. You can have a lot of strength, and still not have the right mechanics for a powerful punch. Maybe if he spent more time with Freddy Roach he'd fix that, but for now he doesn't seem to have that concussion to his punch. Its like Floyd Mayweather - lot's of athleticism, but no power.
You're not supposed to plant your feet. Every top level boxing trainer and manager (including Emanual Stewart, Freddie Roach, Cus D'Amato) has pointed this out time and time again. If the only way you can develop power is planting your feet, you're doing it wrong.