Re: Played a LP Standard with a repaired neck today... Wow!
IMO liveliness resides more in the neck than the body. It took me years to realize that. One of the first things I do when checking out a guitar is to tap the back of the headstock and feel how the body and neck vibrate together.
For those who only think in terms of of tone that might seem pretty silly. But for me it's more about liveness. This is where long tenon necks often excel. Here again, somebody who's concerned with tone alone might not recognize that it makes any difference. And I have short tenon guitars that come alive quite well, but I've found that in general long tenon guitars more often tend to be nice and lively.
A headstock repair might be likely to increase brightness and attack - mine did - which is an improvement for some. Yet it's also likely to add stiffness, reducing liveness - mine did that too.
The upside is, I don't doubt the headstocks are stronger afterwards, and the notorious weak spot shouldn't ever be a problem on those guitars again.