I've been keeping an eye on this thread and have been skimming through the posts as it progresses. I haven't added anything as of yet because I didn't feel I had the time to make a post that would contribute to what had already been said. What I've seen is some very nice discussion but getting stranded in the airport has given me some time to read through the previous posts and put together some thoughts. Here are some thoughts on the topic:
*I don???t think you can ever be fast enough. I tend to think that greater top end speed is the primary key to success in every event from the 400m on down. Dark Knight gives the example of him self and says that even as a 100m guy he can still run a 48 second 400m because of his fitness. I would argue the opposite and say that the reason he can run a 48 is because of his 100m speed. The higher the top end speed, the more speed reserve one has. As a result, running at a given pace (such as your stated 12.5s / 100m objective) for someone who is faster will be much easier and SHOULD have less metabolic cost than someone who is coming to the event with a lower top-end speed. In support of this notion, there was some research in Track Coach a couple years back which clearly indicated that what separates the best from the almost best 400m runners is top-end running speed. For anecdotal evidence look at the top 10 all-time lists (especially the men???s and women???s WR holders) for the 400m and you???ll find that most of those men and women were also very good short sprinters. Also note how well Marion Jones has run the 400m at Mt. Sac in previous years despite never devoting time specifically to the event.
*Having said the above, if you can???t do 8 x 200m @70% with 1 minute rest, you probably do need to address some fitness issues but I still don???t think that would be the primary thing that would be holding you back.
*I like the setup you proposed with 1 day of longer SE, 1 day of shorter SE, and one day of short speed work. I think that would be a nice way to finish off this season.
*As for next season, I think a change from the norm could be very useful. I think a season concentrating on 200m type training would prove very successful.
*Having said that, I have to add that I think that you could go either way (train for speed or endurance) and still see great results the following year. I think contrast in training is very important and often times it seems to be very beneficial to drastically switch up training stimuli not so much for any direct training benefits but more for the gains you will see upon returning to your usual training. I???ve had very good results in strength training with this method.
*Whichever way you go, general fitness should always be the foundation upon which everything is built. Note however that general fitness does not have to mean tons of extensive tempo or long runs.