Agree 100%. If you don't have explicit state transitions in a UI, you're asking for trouble. I think some people don't realize how much harder they make it on themselves by not setting clear boundaries; they see the up front cost and balk, when it saves a non-trivial amount of headache in the future, not to mention reducing mental overhead when you've got the structure hashed out.

Meh. The logic still applies: on a bad network, the first request can hang for half a minute when a retry would get lucky and go through immediately.

Don't handcuff your users for no benefit, just because you can't write a well-behaved backend.