168g Triple Shock has served me well on everything from blesbok up to eland in Africa, and a big old bison bull here in the states. Never a problem with the bullet.
I will admit that I've not shot a blue wildebeest with one, however, my wife did. Shot placement was poor, but it did the job and no problem with the bullet.
I fully understand the idea behind sectional density and heavy bullets. What seems to be left out is that at reasonable distances, the resistance of the air is not the issue, the resistance of the animal is. Therefore, it isn't so much the weight before impact that matters as the weight after impact. The triple shock holds together, so a 168g TSX will do what an old fashioned less durable 180 or 200 grain bullet would do, with less recoil and/or a flatter trajectory. While I happen to like the TSX, any bullet that holds together is going to give it an advantage in penetration over a similar weight bullet that fragments. Therefore, I feel confident using a TSX of lesser weight than what the classic advice would give as optimal. I think tough expanding bullet construction is a game changer.
My son killed his blue wildebeest with a 243 85 grain triple shock, and it only went about 50 yards. I will grant that it was a rather unusual shot: he pulled his shot, hit it in the neck and took out both carotid arteries. Not much resistance to a bullet there, but through and through penetration nonetheless. Since I don't think there is the slightest chance of pulling it off with any regularity, I can't recommend the carotid artery as a target, but it works like nobodies business and by far the best blood trail I've ever seen.