It’s very hard to assess recruiting impact. Michigan has done well in winning some recruiting battles for WRs but not so well at RB. Is Wheatley an impact recruiter? Open question.
It’s also hard to assess a RB coach’s impact on a RB. So much of running ability is instinctual, but some players develop patience. I’ve always believed the main thing RB coaches do is teach pass blocking and ball security. But that may be because Michigan had the same RB coach for a very long time and Fred Jackson excelled in that area.
If Wheatley moves on, I don’t think it’s a big hit. If they can get Greg Roman to replace him (assistant head coach/run game coordinator) with Drevno promoted to straight OC title that would be a big improvement in overall coaching chops in the staff. If they get someone else with a recruiting focus it could be an injection of fresh energy and ideas. You can trust Harbaugh to make a good hire.