I think rotator cuff injuries are more common to pitchers. I'm not going to research it, but I'm certain that there have been many that have come back from the surgery with no ill effects.
I had surgery for a torn labrum and a torn rotator cuff this past July. I work out pretty hard (for an old guy) and right now my shoulder is feeling pretty good. I'm not without some discomfort, but I foresee a complete recovery, certainly within 1 year from the surgery.
A couple of points regarding this. First, my injury was sustained in a hard fall while snow skiing in March of 2004. I waited 1 1/2 years to have it repaired. Therefore, it needed to be "freshened", meaning the ligaments needed to be re-abraided so they would knit. The recovery period was lengthened because of this.
My thinking is that because the injury to Brees was sustained in a fall as opposed to throwing, it is hopefully less likely to re-occur. I'm not a doctor, but if the stress on the tissues was caused by an inappropriate throwing motion, I'd be more concerned. A fall is a fall and anybody can hurt anything by falling.
Additionally, heck...I'm 50. I expect to play tennis this summer and I play with the shoulder I injured. I'm going skiing this week. I'm an aggressive skier, have been skiing most of my life, and expect no ill effects. I've been doing light lifting for a solid two months, and my strength is returning. And folks, I do not have a team of highly-paid professionals monitoring my every move. I really don't think there is significant reason for concern regarding the shoulder.