Jeremy Warner should move to the 1500 meters.
It pretty simple really, all he has to do is the following in order to be able to run 3:25 and break the world record.
Step 1: get back into 43 second shape for the open 400.
Step 2: train to run the 500 meters in 1:08 with a 20 lb weight vest on.
Step 3: train to run the 1000 meters in 2:16 with a 10 lb weight vest on.
Step 4: train to run 1450 meters in 3:25 with a 5 lbs weight vest on.
Step 5: take the weight vest off and run 3:25 for 1500.