I feel this can sometimes happen even when the writers stay the same. Highly subjective opinion incoming! By season 3, the characters on the BBC show Sherlock

I feel this can sometimes happen even when the writers stay the same. Highly subjective opinion incoming! By season 3, the characters on the BBC show Sherlock had become caricatures of their season 1 selves. Though maybe it doesn't help that the characterisation was always a bit over the top anyway...