I ran (distance) for ND so I could be biased, but I think Millar does a very good job with limited money and resources. He's never going to have a stable of sprint studs because of the academic standards and midwestern weather. There is a reason the SEC and ACC rule the sprints. Warm weather and flexible (to say the least) admission standards go a long way.
Millar's expertise seems to be the hurdles. He did a great job with Selim Nurudeen, who was a 4 time Big East Champ and All-American after failing to even qualify for the Texas State Champs as a high schooler. Errol Williams ran 13.5 and was an All-American. He also coached 2 post-collegiate women to Olympic teams in the short hurdles. One of those placed 7th in the Olympic final.
He's also a good 400m coach. Liz grow was a 4x indoor qualifier and multiple All-American. She ran 52.1 indoors. He's also coached multiple walkons down to the mid 46sec range. Last year they had an indoor 4x4 run 3:10 with hardly any money into any of the 4 guys.
Maryann Erigha has struggled at times, but when healthy and fit ran 11.2x and 23.3x .
Give credit where it is due. ND is primarily a distance school, but he has done well there considering. He also coached previously at Arizona State and Texas and has some good credentials from those schools as well.