Love the talk about paces and planning. If only we knew the magic formula! I guess when we look back at the diaries perhaps there were other changes like diet, rest etc that could have a big effect on the body.
My last marathon (a year ago) was 7:42mm pace, PB 7:39mm but I aspire to 7:26mm! For tempo runs I go by Daniels pace chart based on my 10k time (VDOT between 49 and 50) tempo pace is 6:53mm adjusted for longer runs (per jason's post) gave 7:07mm for a 40 minute tempo and that felt ok!
So if true tempo pace is around 7mm then marathon pace should be faster.
All the charts say it should be so maybe I need to believe that.
I think I will be concentrating on much the same as you NP; I'll do more tempo runs - a tempo interval sesion, a longer tempo run and an interval session to keep the legs moving. Easy runs will be slower as the charts show based on above they should be 8:30 - 8:40mm and also MP in the long runs from the P & D schedules.
Last night went to the gym for my strength and conditioning work - squats, deadlifts and some lunges (they were just with the 15kg bar!!). The glutes and quads knew they were being worked!
Hope today's run not too tough NP! 
Teknik good news on the knee.
Stunning day here, better get going on a nice slow run.
F