God did not call pastors to just preach the Word He called them to Shepherd the flock;

To care for their spiritual needs, to lead them in their spiritual journeys, and to feed them spiritual food.

Peter Exhorts pastors to Shepherd the flock well because in the end they will stand before the Good Shepherd and give account for how they pastored His flock while He was away.

So why is it important to be part of a church that has a good shepherd pastor?- Because the pastor is the one who the sheep will follow.