334.80 Ampacity for NM cable seems like it may make installation more difficult and time-consuming by possibly requiring ampacity adjustment of wiring in insulated walls for residential construction. At the very least, it could mean drilling more holes to pull wires through.
What happens when you bring all of your Home Runs down an insulated exterior vertical stud wall bay to a panel board in a basement? Seems like it would be necessary to apply the ampacity adjustment factor of Table 319.15[B][2][a] to all conductors.
I guess unless you have some sort of rack to maintain spacing, it will somehow be necessary to separate the cables so you don’t end up having to run 10/2 for the small appliance branch circuits.
I can't imagine that builders and insulation contractors are going to be thrilled with electricians filling up the whole stud bay with wiring and making it more difficult for them to get the required R-value.
