Three in midfield needed and making one of a two Palmer is unwise and I seem to recall it has been tried before and led to disaster. Playing high risk football not sensible even though DR blames individual errors.
Vaulks was intelligent as a footballer and did the work of two men defending in an under manned midfield in the last few months of the season but did not feel really wanted. He also took over taking the corners from BB, very successfully
Not sure it was as simple as Vaulks turning us down. He said he did not feel wanted and his appearances on video last season when he was often not picked showed he was a guy not afraid to speak frankly. Eg towards the end of the season , about having to play a different way from the way preferred ( by the management) to get points.