Flint and Smithies could have done better but it was one hell of a shot. The swerve on it was ridiculous.
If we can get a fee for Flint (or if his wages are as high as some ITK claim) and if Morrison can get his form back (a big if), then maybe there is a case to let him go. But the priority (which the manager's and board's judgement must be be based on) is staying in the Championship. No risks.
If they don't have confidence in Mozzer and don't see a viable back up plan for centre back with Ng, Pack or A N Other if there is an injury or suspension to navigate, then just keep everyone.
The defence has been poor all season - but I doubt fewer defenders in the squad and fewer options is the right answer (although 4 at the back might be).