I think the work ETHIC is only a part of his reason for leaving DT. Sure his mind and body needs a break from all the physical things, beyond playing the drums themselves, such as interviews, set lists, meet and greets, etc. etc., but I think he also felt the band needed a break because he himself was feeling they were in a cycle that was becoming stale. Whether or not he gave 100% or more probably would not have changed how his feelings on direction of the band was going. From his words, it seems to me that he felt they weren't as fresh as he'd like them to be.
That would be like going in to work and telling your co-workers and bosses and such that you felt THEIR work was becoming stale, and possibly suffering because of it. Would you want THEM to take a break so you could all come back refreshed? Or do you think they would still want to continue, after having some success in the last few years? As a regular, average Joe Plumber, I'm sure many of us would bite the bit and continue working, because it pays our bills, but Mike is SUCH a passionate person, and believes so strongly in his work that he was willing to leave the band over it. He felt that if he went in the studio in January, he'd be "going through the motions" for something that he wouldn't have his heart in. That seems to me he's lost faith in the band a bit, not just because he's grown weary and tired of the machine of writing/recording/touring.
So whether or not he took on less duties in the band probably would not have mattered - the heart of it was is the music, and what he felt was that he wouldn't feel right about "going through the motions" in the studio in January. He never said anything about lyrics (which he admits he probably wouldn't have written any for DT11 anyway), or set lists, or internet forums, or fans, or interviews, or any of those things... it was about the music. The work itself. You may go to work tired every day, but in the end, are you relatively happy with what your output was? Does it please you at all? If you say yes, then you can definitely go to work every day as you do, and be at peace of mind for a bit. If the answer was no, then you have a reason to quit. If you feel the work you do isn't good, or that you wouldn't feel it at all, or it's become almost an involuntary reaction and something you don't do with passion (because music should be passionate), then there's something wrong, and you need a change in setting, environment, and Mike has seen that playing with HAIL, Avenged Sevenfold and Transatlantic all in one year. Different settings and environments opened his eyes to different working relationships and when compared to the one he's known and built for 25 years, he probably felt a change was needed in his own home base of DT, thus the proposition to go on break for awhile.
-Marc.