Succession planning without defined roles, a company design to attract-trust, key result areas and managers with sufficient capacity to handle to current work, is like pissing in your shoe and using all your budget to buy new socks.
Beginning questions for talent pool development.
Are knowing people’s weaknesses sufficient to improve the work?
Few companies know to deal with hiring and promotion mistakes and they repeat them, knowing that they are creating failure and organizational chaos.
Unfortunately the employee, that is now in the role that they cannot adequately fill, is usually punished by termination or sent to training.
You cannot teach a tadpole to be a frog by giving it jumping lessons.
People cannot be taught, coached, developed and/or trained to work at a level of complexity above what they are capable of doing.