That is gamed too. You just don't include the names of people you have wronged: the bugs you have left for others to fix, the undocumented code, the projects you were supposed to complete but got reassigned so that you could work on something with higher promotion possibilities, the delays you cause in other people's work, etc...
This is exactly what I've seen happen in my experience and have often wondered about alternatives. Bridgewater, for example, uses a system that allows for feedback from anybody at any time [0], but I suspect that presents new issues like negative reviews from rival employees. Additionally, a lack of context could result in negative feedback for decisions that actually help the business (e.g. passing on requests to help colleagues with relatively low-value items in favor of focusing on higher priorities).
