It's a matter of balance.
If we had 6 Korkis in the pack we would break more tackles but we wouldn't win the game.

Fergi and Henderson do a good job at what they do. JK obviously likes hard working tacklers. Fergi has more to his game than that but right now, we need a shored up defense, and he gives that.

Dificult to say that I wold drop either for King or PJ as 1) neither have really played to show their worth and 2) they are completely different types of players.
If King comes in it is more likely that Gledhill would be under pressure but right now for me he has earned his place and should keep it.
If PJ comes back he is more likely to take JD or Morrison's place as they are more his style player....and right now that isn't going to happen either.