It shouldnt be an exception, but rather the rule in my opinion. With the kind of schedules teams have to face currently, its almost impossible to keep up the same level in all competitons. I tend to agree with Swag when he says winning the Champions League is a reward in itself, but quite clearly i dont see how teams are expected to cope in these times. The Parma example, quite clearly showed that it can only be one or the other, as a realistic point of view, and Parma chose survival over glory. But as regards the current situation, I just believe as Champions League winners, you ought to have the right to defend your title. And moreover, it doesnt speak well for the level of the Champions League, if one actually looks at it from a viewpoint where the Champions one season, arent even good enough to qualify for the next.
I think we could draw the line somewhere and give teams in such situations maybe a wild card qualifier situation or something.