My insights as a supervisor.
It is tough given the constraints of the OPR writing guides. You can't say something negative without making it a referral. And you can't always count on the presence or absence of a strat...our wing restricts starts to "top 15%" only. Makes it tough when you supervise a flight and you can only give out #1/x because 2/3rds of your flight is enlisted. So, unless you are creative and/or lucky with close out dates...some good people (your #2s) don't always get strats. Meaningful strats are "#x/y CGOs" or "#x/y Lts" and to a lesser extent "#x/y IPs" or "#x/y ACs" and meaningless strats are "#1 pick for..." or "#1 pilot."
However, to write an OPR to "the level of a person's performance" is the key in our fucked up system. This is what distinguishes a bad OPR from a good but not the best OPR. If the person is a performer, the bullets should scream it. Every bullet on a great OPR has meaningful impact and result. Use either "action, impact, result" or "action, impact" format. I prefer the latter personally, but I know the board looks for the former. On a mediocre to poor OPR, the bullets don't pop. They don't show leadership. They read along the lines of "person was here, did stuff, some vague result." Also, the composition of the push line matters. "Continue to challenge" is the classic weak push, but there are other ways. Typically no job push or a weak PME push.
Finally, for the really bad OPR that doesn't fall under the referral process, you have the "spelling and grammar" at your disposal. This requires a note from the rater or additional rater so that the chain doesn't kick it back. Usually to the effect of "spelling and grammar mistakes on this OPR are intentional." I've only seen that used once in my career though.
I don't like the way we do OPRs, but I know how to work within the system to get accolades for my performers and how to communicate that someone is a bump on a log. Some days I wish I could write something like "His officers would follow him anywhere, but only out of morbid curiosity."