When employees report things, but it's outside their direct organizational unit, superiors tend to ignore that as "not our problem".
Also, when superiors block reports, because they might make them look bad, it would be great to have a mechanism, that both (a) lets the employee report it beyond their direct superior without making him look bad and (b) lets the superiors document that the concern has been noted and dismissed with thought.
I'm not so much interested in technical aspects (any Wiki could be used for that, as could Slack or whatever), but how to structure the process, so that employees feel heard, but superiors don't feel unnecessarily threatened.
Yes, working there sucks. That's why there's money changing hands.
Because things are good enough, there's no economic rationale for listening to complaints about them. Likewise, because things are good enough and employees are getting paid to deal with the imperfection, it's unprofessional to complain because you are putting effort into something that doesn't benefit the company.
Good luck.