Sure gives one an appreciation and faith in these Aeronca's and their ability to stay flying even with what appears to be staggering odds! Glad to know people made it home safely!
I have some totally nieave thoughts on this. So please bear with my post and please educate me where I run astray.
1) The blue color seems to be odd to me. Was this razorback (fiberglass) covering? What is the age of this fabric? No matter if installed 100% correctly or not. EVERYTHING ages and most things loose strength or degrade over time. How long is glue good for? I don't know, but sooner or latter it's going to give up and fail. Apparently something reach this point on this aicraft.
2) It appears to me that the only thing holding this bottom fabric in place is what appears to be about a glued 2 inch or so overlap of aparently the top peice of fabric.
Is this legal? 2 inches seems totally inadequate to me! At lest on a wing.
3) The fabric has blue color and then there are blotches of white which can be seen from the front views. This would seem to indicate that there was inadequate penetration of whatever the blue stuff is. And/or the glue held in some places and not in others. In either case not good!
4) The front view also shows a rip in the fabric parallel with the fuselage. Any fabric that I have ever seen and tried to rip by hand I was unable to rip at full strength of my hands/arms. Or if any did rip it was small. It would seem odd that the wind moving at Champ speeds should have been strong enough to have been able to rip the fabric. Which leads me to wonder how strong the fabric(dacron) really was.
5) I wonder if this was fiberglass/razorback if the punch testing of the fabric was ineffective at accurately measuring the strength of the fabric. Rather it was mearly measuring the hardness of the surface where the punch test was applied. In other words. The surfce could be hard as a rock but the fabric underneath not have any strength what so ever. And being hard on the surface would not have even made a dimple when doing the punch test. This would have given the false impression that everything was fine!
6) It sure would seem to make sense for there to be some sort of fabric protector at the rear edge of the leading edge wrap. I agree with MikeB above that a 2 inch tape glued to the rear edge would seem to provide extra protection. Paul A suggests installing a peice of masking tape. I have found masking tape to loose 100% of its adherence after a fairly short period of time. Usually any adhesive on the tape turns to a yellowish/white dust and the tape falls off. I guess since it is surrounded by shrunken fabric it would have no place to go and therefore stay in place and continue to provide some protection. But I would also think that if there is enough vibration/abbrasion to chew through dacron fabric, exactly how long would it take to wear through a single thickness of masking tape?
7) As probably you can tell by now, I know little/nothing about fabric covering an aircraft with what I've said above. But with the beating a leading edge takes, it would seem like common sense that I would want a double thickness of fabric over the entire leading edge. Obviously with the overlapp completely glued to each other. It would also seem reasonable to glue the piece on the bottom to be glued to the leading edge material. Soemone in the post above suggested that these NOT be glued to the leading edge wrap. That may be 100% true. But I don't understand why. I could see stopping the glue on the aluminum wrap an inch or two away from the edge to avoid some funcky things happening with the fabric at the rib locations.
Maybe this gives us all a good reason to go with sewn envelopes instead of blankets? I personally hate seeing the sewn joint. But that is just me!
Again. I do not intend this to be a flame or like I'm some kind of expert. Becasue I'm not by any stretch of the imagination. I just want to offer my thoughts and continue learning.
I'd really like to recover my Chief at some point in the next few years as it was last re-covered in the early 1980's. Everything looks/tests good now and it appears to have always been hangared etc. But maybe the pictures of the Champ above also was testing OK etc. But it still has been a number of years and I just want to check things out and keep it safe, looking good and hopefully increase its value!
. Of course the paint can be broken but the fabric still good. Unsure of Poly-Fiber but the old 'dope' system is pretty flexible regardless of the temperature. Mu understanding is that the new Stewart System is also. Paul makes a good point regarding a felt type covering over the leading edge. If you look at the Oshkosh type winners, they all seem to have a very smooth leading edge. Can't hurt with the airspeed either. 
