I'm with you there, but (and, this is an unpopular opinion) I think it would be even better if it went the way of Go. Go will randomize iteration order of unordered collections (at least in development builds?) on purpose so you learn not depend on it. The "tricky" thing with Unity is that you might find a consistent client behavior and unknowingly depend on it.

I think with time/experience you'll learn to spot what to ignore (frame lengths, etc) and what you could count on. And just to test fully-build games often, and across clients.

* C# does something similar with hash across builds (so you don't depend on serializing/deserializing hashes and expect them to work; they want the freedom to change hash functions).