That seems like a terribly inefficient strategy. A wounded enemy can still be a threat. Just kill the guy & move on to the next target. Moral will be low if their comrades are dead... not just wounded ~ and it's one less each time shooting back.
I've argued this many times on the internet.
While a 5.56 round may have a very low survivability rate, it also has a very low incapacitation rate. That means that while the target will die, for a little while he's still able to shoot back.
And the point made about the types of people we are fighting is also a good one. It is a very good assumption that 1 wounded soldier also takes out 2 healthy soldiers to take care of him, at least for a little while. This assumption stands IF (AND ONLY IF) we are fighting a First World Country. That is, a place that values life. We haven't fought a First World Country since Germany (and arguably, Japan wasn't a first either).
Now, as to the solution? Then we venture into personal opinion. Many people thought that the goal was to find a common weapon for every soldier. But to give everyone an average weapon was an epic failure that we have seen.
I believe the solution is to go back to specialized weapons for each soldier. I.E. Large caliber battle rifles for most, large caliber SMG's for some, and then large caliber MG's for a couple. While it does bring with it supply issues both for parts and ammo, it puts specialized weapons that are able to be used for when specialized situations arise.