But look at it from the client's side. How would it detangle its response to the notify event from whatever it's doing as part of the chained transaction?
The chain writing client wouldn't receive its own notification until after the chain completes and thus would be unable to respond to it, avoiding all of this and having the same behavior as today. It's any client except the chain authoring one that would receive the notification upon each chain link committing instead of waiting until the end of the chain. I'm fine with those other clients having to wait, just as the chain authoring client does, until the chain is over as a matter of consistency - but I don't see how given those other clients earlier access to the notification risks being considered here. We are already doing that now, though I argue we are in fact documenting the "other clients receive the notification as soon as committed - regardless of chaining" situation (the additional restrictions on receiving are then what cause the chain authoring client to wait).
