Pro:
1) Continuity with a returning 5th year QB who is very good (though not elite).
2) Player satisfaction and recruiting continuity
3) THIS IS ALL THAT KELLY COULD GET. He has a rep for being a dick. Several assistants have left with their reps the worse for wear under Kelly. He will throw you under the bus if it helps him. On offense, Kelly can't keep his hand off of the wheel. It is what it is, ND had no other options wrt to proven commodity at OC.
4) Rees appears to be willing to stick with the run game more than in the past (from the extremely small sample size of n=1)
5) Cheap hire (this one is sad, but likely a factor given the salaries good assistants are drawing these days).
Con:
1) Unproven
2) Learning on the job at a program that should be above this (no disrespect to Rees personally, but his experience level is almost nil as an OC at this point).
3) 90% of Rees' knowledge of the game comes from Brian Kelly's staff. A staff that had 3 of the 5 first team All Pro NFL offensive lineman and yet still chose to thow fades to the corners on first and goal - especially in hurricanes.
4) Lacks the gravitas to stand up to Kelly when he needs to do so (Full disclosure: Brian Kelly likely considered this to be his best attribute).
5) Other schools are going to beat on this green hire on the recruiting trail.
5) Not very good at parking cars.
Hope it works out. i will be cheering for Tommy Rees, but holy crap.