Passive: Scale with AD instead of AP
Heal on W: Scale with AD instead of AP
I just got myself Diana and am having a blast with her and all of her abilities scale with AP, and so does her passive....why not do the same for Kha'zix (except with AD of course). There is no reason to get AP on him at all, he is squishy and can't really help end game. He isn't useless, just super super difficult to play well end game and if you don't participate in your team fights because waiting to jump in you are weakening your team.
I propose we just make his passive and his heal off of W scale with AD. Don't make the heal anything huge, but maybe .5 of his AD, help his sustainability end game a tiny bit.
If you do the passive change you'd have to have it scale harder end game and slower early on in order to keep him balanced early on. But if you have it scale end game at .35-.4 and early on .1-.15 it'd help a lot.
He is a blast to play, tiny buff would be wonderful!