He has good stuff. I'd certainly rather see him closing games than Doug Henry. Felix Jose will probably benefit for now, but I'd guess the Yankees will be burning up the phone lines trying to acquire another bat. I doubt that he'll fall off the planet or anything. But I'd also be surprised if he won 20 games, and if his ERA stayed below 4.50.
Every pitcher is different.
The conventional wisdom is that power pitchers tend to last longer, which certainly bodes well for the Big Unit. But they'll be awfully good. I'm getting killed with SB's and have Furcal and Febles on injured reserve. Furcal has hamstring problems, and I'd guess that the Braves will be cautious about letting him run much until he's totally healed. I wouldn't count on him being as much of a stolen base threat in the second half.