Dont freak out if there is a mistake in these stats, because i did it quick.
Since joining their current teams (2010 for kelly, 2014 for Peterson)
Overall = 76-34 (kelly) - 69.1%, 43-19 - 69.4% (Peterson)
Vs. Teams that were ranked when they played them = 16-16 -50% (Kelly), 7-13-35% (Peterson)
Vs. Teams that were ranked at the end of the year = 13-22 - 37.1% (Kelly), 4-12-25% (Peterson)
If you wanted to go for both coaches since 2010, Petersons numbers obviously go up for total winning %, but not much for anything else considering his competition dropped significantly. So this isn't really the best comparison to do, because i could really go back to say 2008 and let kelly's states get inflated with wins an Cinnci, but regardless, since 2010 for both coaches.
Overall = 76-34 (kelly) - 69.1%, 86-28 - 75.4% (Peterson)
Vs. Teams that were ranked when they played them = 16-16 -50% (Kelly), 11-15-42.3% (Peterson)
Vs. Teams that were ranked at the end of the year = 13-22 - 37.1% (Kelly), 6-15-28.6% (Peterson)
So... given all this, i really find it a struggle to believe the people that think that Peterson would be this huge upgrade over Kelly... I think they are both really good coaches, but i think Kelly is better. Is he top 3? no, but you could easily argue he is top 10.
he made a terrible hire in Vangorder, and it cost him a ton of wins from 14-16, don't forget, in 2016, they had double digit leads in 3 of those game, and led at halftime in a couple more i believe. He has not always gotten the $$$ from the university to hire and keep good assistant coaches.
Regardless of his future here, ND should always respect what Kelly did here at ND. He brought this team back from nothing to making them relevant again. Made the team exciting, made kids want to consider coming here again, stadium upgrades, turf, practice facilities, locker rooms, etc. He had a huge part in all that. No 100% because of him, but a big part of it. He could leave tomorrow and i would have no hard feelings about his time here. I have wondered from time to time if both need some fresh air and it is time to move on, but he seems happy staying right now. He may not be everyone's favorite coach, but he is a damn good coach. Expecting anyone to come in here and win 11+ every single year, is foolish. i have always said that you need a coach at ND who averages 9-10 wins a year and every 4-5 years is in serious contention to make the playoffs. Also, when evaluation coaches and players, i always thought it was much more representative of their true stats when you remove their best game and their worst. You do that for kelly and he is average 9 wins a year. I would like this closer to 10, but i think he is coaching better now then when he started.
Dont forget, Holtz once when 5-6 and 6-5, Knute when 5-4, woody hayes went 4-5 and 3-5 (and was 6-6 in bowls), bob stoops is 9-9 in bowls, jimbo fisher when 5-6, paterno - 3-9, - meaning really good coaches can have bad years.
In my opinion, there aren't a ton of better options to replace him, and the ones who are, don't seem to be looking for the extra challenges that come with Notre Dame.