I'd love the idea of separate tabs for whispers as well. In fact, I'd personally enjoy it for any type of different chat (local, party, group). Perhaps with a toggle-able option to let buttons light up or slowly flicker when a chat you're not looking at gets a new message. Chat commands (especially /silence and /silence*) and game localization also sound lovely.
However, I also agree with WolfQueen and Azura about the karma system. Even if it's not intended to reward players, a counter that goes up for "good" reports (even if it doesn't do anything) may just make some players unecessarily eager to rack up a sort of "morality" or "staff's pet" score. It might help if this was implemented in secret and only visible to staff, but even then it's hard to decide how trustworthy individual in-game reports are at times since ways to supply evidence in-game are a lot more limited, so I'm not sure staff would get much mileage out of it.