Great that someone have written this down. These points should be stressed as much as possible. Anyway, after you move from RPC to message passing and then to

Great that someone have written this down. These points should be stressed as much as possible. Anyway, after you move from RPC to message passing and then to state machines with delayed action execution you are facing the next big problem: the fact that message queues between the components are not perfectly elastic and can run out of memory if different components run at widely different speeds. This is mostly not a problem inside datacenter, where admins take care not to run out of resources. In the Internet environment though it is often a common case rather than a rare occurence. I haven't seen this problem addressed so far, whether in software or in theory. Any pointers to relevant work are welcome.