The problem is that with a 2d platformer, pits in levels are rarely used because of the uncertanty in what defines a pit. In Unreal or Quake arena, carefully going to the edge and peeking down will tell you if jumping down is possible. In platformers, it's more of a guess, and a guess that more often then not turns into death leads to frustration, and the player joining another server.

Few of the original games use the deathpit idea in their levels. In fact, Biomenace and Duke Nukem 2 are the only games in my limited platformer knowledge that used the "Kill you at bottom of level" feature (JJ1 appears to have the same function, but in the original levels, that's more of preventive measure against bugs), but even then, it was extremely obvious to the player that falling was not a good idea.

E4L1 in DN2 was very stressing. That level, which had you swinging on the underside of a spaceship, was very frustrating due to making sure I did not fall off of the vines.

In the defense of the trick, abuse of such features is common when they first come out, until a understandable "code of conduct" is decided on for them. Just look at the evolution of the multiplayer levels in JJ2. It's rather rare now to see shields, and carrot crates / barrels in MP levels, simply because of the game balance.