FWIW the reddit you link to has some replies with very reasonable explanations for the behavior you mention. As they state, I think the deal is even if it fails, it failed _after_ it started, and thus the start itself was successful. I think this is reasonable. I also got all log entries when reproducing here (same result as everyone else in that thread).
I'm not saying deleting bugs is cool - at least a WONTFIX or link to a DUP is appropriate - but are you sure it was opened successfully? What was the bug #?
The above said - I do see your point from a usability, if not strict "proper functioning" standpoint; previously for forking services that did some sort of constant time initialization and checking (opening files, sockets, etc) if the initialization failed they could report back and the startup script could return that result - systemd doesn't seem to support that. However there are other problems with the old way too (as you're checking result code I assume you're scripting) - startup could hang and you never get a result.I suppose the solution is similar for both cases - pick a point of time in the future and check if the status is as expected.
Maybe this is a feature request? As stated in the reddit, it only makes sense for forking services. It's not something I'd ever want, but maybe you could give a use case?