To me, I would use #12 as a minimum size, just because I am that way [wierd?].
If [actually when] I wire my own House, #12 cu will be the minimum size [might go as far as using 15 amp c/b on #12 cu!].
Plenty of circuits, so 30 years down the line the ampacity per circuit will be hopefully available [if needed] without crawling thru the attic. Also to keep separate circuit for rooms, so rooms can be "isolated" if needed.
Once again, I am just that way! This would make the typical Tract wiring EC go broke, or bid 3 times higher than even the most highest bid! Possibly would workout for an EC doing Custom Houses with Clients who want a "Custom, Above-Average Electrical System".
As far as Boxfill, I have become reluctant to concentrate a lot of splices in any outlets / J-Boxes [unless absolutely necessary]. Also prefer to use large, deep Boxes and splice everything before hanging the P-Rings - that way all the wirenuts can be easilly set to the side[s] of the boxes. Of course this is not the same with PVC [Non-Metallic] Boxes - except placing wirenuts to the sides.
My biasing is due to the almost zero amount of Residential work I do, plus only have done a total of 4 tracts, 3 two story Apartment complexes, and 4 Custom Houses in my entire 18 year Career as a sparky.
I just do not know how critical things are in the Residential wiring frontier
It's hard to make good comments when >95% of my work experience for 18 years is in the Commercial Fields.
Dspark:
I was going to say the same thing about back stabbed Receptacles! You beat me to it
(snipped text)
Here's a killer reason for you: 3. No more backstabbed receptacles! (snipped text)
Scott SET