IIRC, orcs seemed to live a little shy of 100 years, but start at 15ish and last little over 500 hours. In a worst-case scenario wither could take 10 years, you're probably losing 50 hours of play. If you're hit by 5 aging withers, based on what I've seen you're talking between 15 and 50 years removed. Let's average that to 25 and say you lose...125 hours. I haven't found an orc being hit by 5 aging withers.

Note: This is all VERY rough guestimates.

On the flip side, I went through QHCF and there's not even a dozen age-death orcs I could find *EVER*. Most of those are the rare orcs that make Chieftain and past the 300ish "barrier" that characters often are deleted. Looks like 1 orc died from a questy effect, Lokloq who wither may have taken SOME, but not enough for me to think it was the only reason he died so early. A 3rd one was really early, but if I recall correctly when that one died, it was a combination of wither and a nice/nasty +age item.

Overall, if 3 characters in 15 years have been hit with it in a manner that actually impacted their character...it's not something I'm really convinced is causing a problem.