In that story, he supposedly needed to be rebonded. Not because one half was "good" (that is, wussy and indecisive) and one was "evil" (that is, impulsive and selfish), and not because these faults seemed to be deepening with time, but because the splitting was having consequences on the physique of both the duplicates, meaning both would die soon.
In "Second Chances", the two Rikers were neither mentally nor physically deteriorating, and if where were any changes in mental or physical capacity originally, those were too slight to be observed.
I said similar.
But you make a good philosophical point. The were not "good and evil", as I put it, they just had tendencies leaning in that direction.