I wish you karma
This is about as neutral and judgmental a wish as I could think of to give anybody. Karma says nothing about what, specifically, you want to wish upon someone. It leaves them to decide what they deserve of karma, but more importantly, it leaves you to decide what you think they deserve from karma. Now, that sounds negative, but it could also be used in good situations where it’s pretty clear whoever you wish it upon deserves something good for what they had done, possibly to or for you. In such times, you could chance wishing happiness, wealth, health or whatever. That’s all good. But karma? Karma will really see to it they get what they deserve in probably more ways than you can imagine… or know!
That means it could also be used in neutral situations where you’re not sure of someone’s character, whether they did good or bad to you. Wishing they get what they deserve is about as fair as it can get then. You can’t go wrong. 🙂