I am illustrating a point; Kha'Zix is reliant on Isolation to do his job, which is kill high priority targets, and any team with a brain between them can effectively prevent that by using the buddy system.
That is goddamn sad. Any other assassin in the game can make a kill in the middle of a teamfight, risky as hell that may be. Kha'Zix cannot, and it is not merely up to possibility as it is with other assassins, they can accomplish that, but is nearly impossible for the Voidreaver to do likewise because of an explicit mechanic in his kit. What distinguishes Kha'Zix further from most assassins is that a target can be completely separate from a teammate with no hope of assistance, yet a single minion can effectively deny Kha'Zix the ability to unleash his maximum potential damage.
No other assassin is weighted by the same stipulations. Katarina, LeBlanc, Zed, Talon, Rengar, ie., can deal their damage without having to worry about a silly minion wandering too close and completely nullifying their damage.
To tie in this lengthy explanation with my attempt at humor, which you did not hind amusing sadly, it is best recommended that any Kha'Zix avoid confrontation unless they are absolutely, positively certain their enemy is completely alone, which means no teammates or minions.