Charlton seemed to be a decent OC choice as he had one year of experience as an OC/QB coach and he had 3 years experience as a head coach. I thought if he proved himself as OC, he would be in line to succeed Mora as head coach. Unfortunately, Charlton did not really work out although I don't judge him on year 1 due to injuries.
Unfortunately for Mora, he was kind of handcuffed by money in dealing with Charlton. UConn's assistant coaching salary pool is about $1.8 million per year, so there was no way UConn was going to pay Charlton ~$900k to walk away this year although Charlton had to know he wasn't getting the job done. Getting rid of Spanos was a money issue as well.
UConn can get decent assistant coaches, but they have to look in the right places. If you want to hire a successful OC or DC, you are going to have to look at lower level coaches from maybe some G5, FCS, or D2/D3 as you will not be able to hire a successful P4 OC or DC without some luck. UConn was able to hire Lashley because he needed to show what he could do on his own and only lasted 1 year.