I don't think it's reasonable to place the blame for Sutton tanking the program on Mills.
Mills was introduced on May 1, 2017 with only 16 remaining days in the late signing period ( April 12 through May 17 ) and was only able to add two additional players in time for the 2017-18 season (only one of which played during the 2017-18 season). He also allowed Spencer Sutton to stay on the roster when there was zero reason to.
Emir Ahmedic signed during the early period on Nov 16th, 2016
Ruder signed under Interim Coach Perry on April 26th
James Conley signed May 15th (only played two games)
Sam Kearns signed on May 17th
The schedule for 2017-18 was already in place when Mills was announced and the majority of the roster (except for two spots) was as well.
This season is a different story, Mills has his first recruiting class in (a step in the right direction) and built the schedule so this year's record is fully on him but holding him accountable for Sutton's rosters and scheduling doesn't make sense. ORU is trying build back up from being one of the bottom 15 programs in the country; something that can't be fixed in a single turn around season.