Double Jump is a good mechanic for providing advanced platforming.
Increased gap/height distances may require more skill, makes the basic platforming easier as well.
It all depends on what kind of platformer you want to make, and what kind of gameplay design you want. A lot of games don't have double jump because it makes their platforming too easy. Other games use doublejump as a crutch, and other other games makes platforming too hard because with doublejump, jumping puzzles will have more death/failure areas to provide difficulty.
In the end it shouldn't hurt too much if you keep in mind what kind of difficulty/design you want. If it takes away from the game quality you can easily remove the double jump.