Hey Chimpy - the whole point of SML is to get decent owners to compete in our league. You are exactly that and it would be a great loss if you sat out next season waiting for M13.
You proved today that you are a 'fair play' guy - losing to a cpu team is a rarity but it does happen - and some players would have re-started the game but you showed real class in taking the defeat.
We all lose the passion for Madden at times because the flaws in the programming go against you but as Jensua has said, he is also not 'feeling' Madden 12 any more but will hang in there till M13 comes out. Dont get me wrong, i'm not trying to guilt you into staying but why dont you give it a rest for a week or 2 and see how you feel.
Either way, you've been a fine owner and a fearsome competitor - if you choose to sit out next season you will be sorely missed, not to mention Brza's Eagles having an easier schedule!
Take some time out and see how you feel before quitting. It worked for me.