It does sound as if you occupy a distinct spot in your organization’s culture, and as a result, you may be uniquely situated to spur improvements. But before you proceed, make sure you don’t fall prey to Irreplaceable Me Syndrome.
That’s the Workologist’s name for a common malady: the well-intentioned belief that only you can assure the brightest future for your enterprise. (Usually this manifests itself in the form of guilt about quitting a longtime job for a plainly better opportunity.) Keep this in mind, because you’re teetering on the edge of trying to solve problems that are not your responsibility. Managers should not require a mole to understand workers’ views — and workers should not make their futures contingent on someone else’s intervention, however benevolent. Finally, being “friends” with co-workers can be a mixed blessing, so make sure you’re careful to separate professional responsibility from personal obligation.
Perhaps next time a lower-level employee expresses a legitimate grievance, you should encourage that person to formulate a way to make his or her views known to someone who can actually do something about the problem. You may even have strategic advice about which manager would be best to approach, and how. But either way, bear in mind that what feels like gathering useful intel about how an organization can be improved can very easily cross over into listening to aimless venting and grievance gossip. That’s very human, but the person it helps least is you.
You can also consider ways to translate the critiques you’ve heard into suggestions to higher-ups that won’t involve betraying confidences. (Floating possible solutions is always better than listing problems.) If you’re worried that you’ll be perceived as abusing your inside knowledge, you can road-test your thoughts: “That’s a good point about problem X, and I’m on good terms with manager Y, so what if…