Actually, I am quite disturbed with implications of shifting the burden of fees to the receiver (as transaction fees are at least partially dependent on conditions that only the sender is exposed to, such as for instance whether the sender's balance is made up of a bajillion of tiny 0.5 BTC inputs)
I'll PM theymos so that he can convince me without turning this topic into a rehash of something he might have already discussed and explained in detail
With OP_EVAL, the fees for inputs will stay with the sender, while the fees for the output are moved to the receiver (who'll pay them when he uses them as inputs). So what OP_EVAL does is make everyone responsible for their own stuff.
Ah, now IC the rational core of the concern, no need to bother theymos
However... How does the receiver get to know what his fees will be like ?
Let's say I want you to send me an escrow-OP_EVAL transaction. I want you to send, like... oh, 5 BTC.
It would be very unkosher if there would be no way for me to know in advance what fee to expect "on my end" after the escrow authority signs stuff (oh noes, it ated 3 BTC out of 5!
)