Track events are 90-95 percent aerobic. You should be able to run fast off of high mileage(I.E. Edward Cheserek runs 3:49 indoor off 120 mile weeks) and mainly aerobic interval sessions. The way you can rebuild your turnover is start with light 80-100 stride sessions 2-3 times a week following 45-70 minutes of aerobic running. Doing drills such as A-skips, B-skips, quick high knees, and butt kickers may assist in recruiting fast twitch muscles and wake up the muscles that are used when going at a quicker rate. During preseason track (about 4 months out from your peak race) while you are doing aerobic work such as tempo effort type of work outs, you may include some short 30 second hill sprints that will teach your body to maintain form and recruit fast muscle fibers.
The main bulk of your workouts all season should remain 800m reps-Mile reps to build strength. About midseason (2-3 months out from your peak race) you can start incorporating 200 meter build up strides (about 4-6) after a 45-70 minute aerobic run. You can progress 10k-5k-3k-1500-800 on those 200's. Focus on form and turnover. You only need about 6-8 weeks of race pace workouts that will get you as ready as you possibly could for your scheduled peak season. You only really need to "sharpen" up with a few work outs in your "peak phase" during those 6-8 weeks, you can start incorporating workouts like 10x300m at 1500 pace with 30-45 seconds rest, 3-4 x 600 @ 1500m pace with 2-2:30 rest, 8-12 x 400 with equal rest(whatever you split for the 400 is your rest), or break down type of workouts.
Keep long runs 14-18 to develop aerobic base (not abnormal for track athletes to even hit 20 milers). Hope this gives some direction.