I've seen it keep coming up in various places and now in Daniel's 4th edition of Running Formula these comments about how marathon pace runs in training aren't physiologically more useful compared to easy/moderate (say, at aerobic threshold) training runs.
Daniels notes in the 4th edition (not sure if it was there in earlier editions) that the main benefits of MP runs are mental - building confidence, getting to know the pace - and do not have significant physiologic advantages over his easy runs.
I'm sure in the era before GPS watches & HR monitors, that dialing in MP was essential to avoid starting out too fast or too slow. But now?
All marathon plans I've seen urge at least some MP runs. Yet I'm curious if others have seen coaches or plans shift towards recommending instead to reduce MP runs and increase easy run volumes (since recovery needs are less, and you get more volume) or replace with easy run + a bit of threshold pace (more aerobic stimulus?)