Yes and no.
No, I don't think the Patriots will see a huge drop off if he leaves.
Yes, I believe he (particularly if coupled with Josh McDaniel's) could turn a crappy team such as the Lions, Chiefs, Raiders etc around in 2-3 year.
NO -- Scouting even more than coaching is a team effort. If Scott leaves the structure by which the NEP assess players will still be in place. While Scott's opinion of a player will be missed. It is only one voice among the scouts and coaches in deciding on a player. I doubt there have been situations where we drafted a player nobody else like but Scott liked nor avoided an eventual bust that everyone else liked and Scott didn't.
And yes, he is our capoligist. A role that is not nearly as difficult as it once thought to be. I bet Miguel could do the job just fine.
YES -- While Scott is not the entire scouting department. He knows exactly how a winning team does its player selection, training camp, off season program, game planning, etc. He should be able to duplicated that elsewhere.