As has been said, there's no point in trying to legislate each and every thing that's not allowed on your game. People generally know when they're being an asshole, whether you made a rule against that particular kind of behavior or not. I believe strongly in more general "don't be an asshole" rules when it comes to general behavior. (I know there are also more specific rules when it comes to stats, sheets, etc. This is different.) The more specific your rules in regards to behavior, the more you'll get asshole players who will toe the line just shy of crossing it while laughing at you on the other side. I've staffed on games where we've been reluctant to bring in people acting like assholes for a staff chat just because they aren't explicitly breaking rules, and it sucks. A lot. Everyone ends up frustrated, because you feel impotent as a staffer.
Here's what I feel like you owe players: a general sense and appearance of transparency, even-handedness, and fairness. I believe strongly that the appearance of fairness is just as important as fairness in practice. Here's what you don't owe players: constant negotiation, an ear for every complaint, to staff exactly how they want you to staff, or constant satisfaction or happiness. It's much more important that you and whomever you choose to staff with are in agreement about what game you're running and how you run it than to try and make your game fit what every single player wants your game to be. Stick to a vision and a general philosophy, and the players who like your idea will stick around, the players who don't like it will leave.
My parents used to describe their parenting style with me and my three brothers as "we don't negotiate with terrorists." I think it's pretty relevant to staffing, too. You owe it to players to be reasonable and forthright. You don't owe players constant negotiation. You make the rules for your own game. It's not about not listening to players, it's about being able to recognize workable issues versus whining. There are people who just need to whine, but you don't have to sit there and be their receptacle for it. I like to think of staffing as a benevolent dictatorship. I want to cultivate the kind of game where people feel comfortable and chill and have a good time, but at the end of the day, I'm in charge and you're not.
I definitely agree with the previously-stated sentiments of praise in public/chastise in private. I believe super strongly in staff confidentiality. I don't think that general complaints of "this guy's being an asshole a lot" mean that those players lodging complaints should necessarily be privy to the details of how staff handled the issue. This is different for more serious cases of abuse or harassment, but for me that's a more immediate bannable offensive, and I do feel that when it comes to bans, going public with certain information is appropriate. I mean, for me, you have to be a real shit to warrant a ban, and the game deserves to know what kind of behavior warrants such a reaction from staff, IMO. (Full disclosure, I've never actually had to ban a player or been a part of a staff that banned someone during my tenure. I did staff on a game that had a major banning of a very involved player a year or two prior to my joining the game.)
I totally get being sensitive about feeling like you have complaints from all angles. I don't know how to teach someone to reduce their number of fucks, because I've always just had a certain talent for it when it comes to stuff like this. Like, in some ways I totally believe that my job is not about pleasing players; it's about creating a good game. I feel like that maybe makes me sound like a total tyrant, but it's more about recognizing which complaints are actionable and which are whining.
You will never, ever, ever please all players. Some players are just not meant to be pleased. Empower yourself with that knowledge!