It's a good theory but I don't believe Em is struggling at all to repeat the success in lyricism & flow he had when he first came back. 'Forever' was a Boi-1Da beat, and he effortlessly nailed that verse. Same with Chemical Warfare. On any guest appearances pre-2004 he nailed it, Aftermath/Bass Brothers beat or not.
I think it's more along the lines that he believes this is the style that his fans want, which for the most part it was evidently from the good reception its gained since Recovery was released, so he reaches for it and may be struggling to perfect it.. At times he can slip up with it and we end up with a sub-par verse.
Or he could just literally be dumbing it down and/or half-assing shit, but that's the easy answer.
