Basically what Job JGB said; jump cancelling really is needed for only a minute amount of existing jumps, and said jumps generally aren't common in the average needle game.
Also, @BaronBlade, if I recall correctly, GameMaker can't process a press and a release on the same frame; one framing is pressing jump on one frame and releasing it on the next; also, the max jump height is somewhere in the 20s, seeing that the Leehe triple diamond requires a 19-frame jump to pass the first diamond.
Standard gate jumps can be done with 3- to 5-frame jumps if you don't include cactus.
Edit: 900th post hyip