Speed work / race pace work is important, BUT NOT THE BE ALL AND END ALL.
I listened to a Flotrack interview a few years ago from Dave Smith of Oklahoma State and he said (me summarizing), “Workouts are overrated…we just need to get them fit aerobically and sprinkle in some leg turnover stuff and they’ll race fast from just about anything from the mile up to the marathon!”
If you aren’t aerobically fit, IT WON’T MATTER how much race pace work is put in.
GET FIT FIRST.