It's a fundamental precept both of real life and of good fiction that a person's greatest strengths are also their greatest weaknesses and often vice versa.
For example, the character who has an indomitable will, that allows him to persist against incredible odds, generally is also pigheaded when he is wrong. (Something DC failed to do with silver age Green Lantern Hal Jordan -- who is almost preternaturally reasonable in applying his strength of will -- but, if I recall correctly, used properly with Kyle whatshisname.)
Well, this principle is being tested now in biology, where scientists are using HIV's fast mutation rate against it. They have done trials with a new drug called KP-1461, which takes the place of the cytosine and thymine base pairs during reproduction, quickly mucking up the genetic machinery.
It's certainly an interesting idea, but I'm not sure it's a good one. Sure, given that mutations are overwhelmingly nonpositive for the mutated organism, an increased mutation rate in HIV should lead to a decreased viral load. However, given that there are billions of HIV virus "cells" in any given patient, aren't we giving them a pretty high aggregate chance to win the genetic lottery with a really good mutation? Especially if we use this on thousands or millions of patients?
One thing you have to remember: sometimes a strength is just a strength.