Without reading the post but only reading the title, I knew that the answer was going to be no. 8:35-9:00 is acceptable. However...
I would think that 8:00-9:00 should seem very easy if you are in 3:07 marathon shape. Usually when I hear of relatively faster guys running that slow for easy runs the reason is that they are running high mileage (probably 70-100 mpw). I believe that the benefit of running slow slow easy runs is that it allows you to really get you mileage up.
Your long runs should not average 8:00-8:25. That should be your pace to warm up for a few miles before you speed up some. A long run isn't an easy run and it shouldn't be slow.
Long story short: I don't think that you need to run as slow as you are if you are averaging 40-50 mpw, but you could use slow running like that to get up to 70-80 mpw (averaging for many weeks, not a 1-3 week peak) if you have the time.