So then I am confused. Are you suggesting that we guarantee the execution order for these Session-local syncs, or that we allow these Session-local syncs to be executed asynchronously? Because those are largely incompatible ideas (asynchronous execution essentially precludes ordered execution).

I was proposing that the unified syncs could go beyond JTA in this manner (executing CacheSynchronization hooks in the order the javadoc says, and pass the instance to all invocations).

I am very confused by this statement. What is "CacheSynchronization"? According to what javadocs (the javadoc snippet you pasted says nothing about order)? Pass what instance to these invocations?