Nidalee's punce is fine the way it is and should stay that way. It's that way so that you cant just randomly keep juking around with your leaps that have a 3 second cooldown without your enemies having AT LEAST an idea. Kha'zix's Leap is an AOE cursor because it does more damage, is EXTREMELY far when upgraded, and has a 20 second cooldown. Her leaps are meant to get out of sticky situations, not to engage. She can jump through the Golem walls, small cliffs, dragon and baron pit, and just leap. If you are level 6 unless the jungler has a stun there is no way you can be caught as nidalee.
All her leaps are meant for is to get out of sticky situations, wheras Kha'zix's was meant to engage. If you don't like her leap, practice it, or don't play her.