Down from 800 m to 400 m training plan - what u think?

do you not have a coach?

either way, don't overthink it. just google "clyde hart workout" and you'll be good.

and before you protest: no, you're not smarter than the best 400m coach of all-time.

too much endurance/long runs

if you are a 400 guy trying to break 49 you need speed more than anything else

Where are the weights? I know you do jumps, but to run a sub 48sec I think weights are an essential part to make that happen. If you can do 2 or 3 weight sessions a week you also have to do a little less track work which will help you stay healthy. Also, as mentioned before, there's no reason to do 2 long tempos a week. Even 1 might even be a lot.

I would also add an overdistance workout in which you work on your speed endurance a bit. This is kind of in the middle of the workouts you are planning (speed vs. tempo runs) and I think it will be beneficial to do something like that. Maybe something like 600-500-400 around 1:26 - 1:10 - 53 followed by a couple 150s just focusing on form.

I don't think you should just copy someone else's training schedule. What works for someone else will not necessarily work for you.

Tons of people on Charlie Francis's forum have had good success with this program.

http://www.charliefrancis.com/community/showthread.php?21613-Kit-kats-400m-program&highlight=kitkat