I've been following this thread for a couple of days and have enjoyed it so far. It's gone off on a few tangents, but for the most part it is interesting.
For me, it's been interesting to think about why some people think one aspect of training might be overrated while someone else thinks the same aspect of training might be underrated. I have a few theories and would love to hear what others thought.
One possibility that I think is probably the most likely: One person came through a training program that overvalued one thing, where someone else might have come from a program where that same thing was absent or at least not prevalent. Example: Runner A's coach demanded that a long run be completed every week no matter what where runner B's coach did not believe in the long run. Later on, runner A decides to scrap a few of his/her long runs and replace them with a progressive run and boom improvement...the long run is overrated and progressive runs are underrated. For runner B, the long run was never really incorporated because coach wanted to make sure there was time in the week to do another quality track session. After moving on, runner b decides to incorporate a long run, sees major improvement and now long runs are the secret ingredient and too many quality sessions are the devil.
Another possibility is the exact opposite. Maybe runner A and runner B never moved out of their original programs and had strong willed coaches who had them totally convinced. Runner A might just think that because he/she has always highly valued the long run and that message has been sent so often, that that's the way it is and the same with runner B and his/her affinity for quality work on the track.
It seems like most, if not all of the components of training are valuable in some capacity, but it is the balance of them within a particular training program that defines their value. I agree with those who say that the balance will be different for different individuals. I think it is more complicated than that though as the balance will change even for the same individual over time. As a runner's skills and strength improve one modality might become more necessary than it used to be and one might take a backseat.
This brings me to my last possibility which is the question of when. What I mean by that is when do we want to see results. If an athlete is always looking to maximize potential in the short term, which may even mean 6 months down the road, they may have a different concept of what is overrated/underrated vs. the person who wants to see how fast he/she can be 6 years from now. If runner A wants to run a half marathon every 6 months and run as fast as he/she can at each one of those, the priorities might be different from someone who wants to run really fast 6 years from now, see steady improvement along the way, but maybe not care if the intermediate races aren't run at tip top sharpness. In these circumstances, runner A might not put a lot of value into drills, core strength, hip strength, and biomechanical work in general because those things take a lot of time and probably won't produce a big difference for the race in 6 months, but runner B might put a lot more stock into those components because they are things that might help to keep a runner healthy over the next 6 years and might enable that athlete to stay healthy while continuously adding mileage. There may be an argument over how much work is sustainable, but I don't think that anyone would argue that if they could figure out a way to add 10% to their workload and have that be sustainable, it would help their performances regardless of event.
What does letsrun think about any of that?