What gear ratio? Usually the 3.50's are pretty strong, but when you get to the 4.56's the pinion gear is pretty small and weak.
Not much of an issue with smaller tires, less off-roading, or a lighter right foot. But weaker it is.
The 4.11 is still weaker than the 3.50, but it's not too bad as long as you don't keep putting your foot into it when you shouldn't. But as mentioned, a lot of that depends more on the tire size than anything else.
The u-joints can get whacked at just about any power level if that power is being applied while turning. They lose quite a lot of their resistance to breaking as the angle increased. It's shocking actually, so it's good to always be mindful of the wheel position when you're about to get on the gas to get out of a hole.
You off-roading much? Or was this just a case of an old part letting go?
You could replace the stock lockouts (locking hubs) with aftermarket versions if you have not already. That might turn the hub into the "fuse" and take one more step away from the ring-n-pinion. Might be worth looking into, even though it's tough to lose the strength of the stock locking mechanism. Gives you a choice though.
Paul