He was a much better batsman than Wasim Bari but a mediocre keeper, and this was an era where keepers weree judged purely on their keeping skills. In the pre-Gilchrist era, runs from keepers were a bonus.
Wasim Bari was one of the greatest keepers of all time. There was no way he was going to lose his place to Taslim Arif, who was quite old himself by the time the former retired.