I use these flashes a ton. I've probably got 40,000+ shots spread out between the two 580 EXII that I own. I use them wireless and on camera for a bounce/fill, often at the same time.
My problem is that they get hot and need to cool down briefly, after about 75-100 shots of continuous firing. I'm glad I have 2 because at wedding ceremonies and receptions I often can't go without a flash and having the spare has saved my ass. After letting the unit cool down for about 45 minutes it's able to handle a load again. I'm usually running it at +1 1/3.
Hence, make it more efficient! Having wireless would be awesome, too, but may dramatically increase the price. Keep it in the $500 range. 200mm isn't important to me but would be nice. Everything else about the unit is great for me, but ignorance is bliss. I'm always still learning.