1. A system for skeleton-based discovery of an application in a computer network, the system comprising: a processor configured to: generate a template for an application topology of the application based on a structure determined by an initial discovery and retrieved from storage, wherein the application topology is multi-tiered and comprises: nodes associated with elements of the application, and dependencies between the nodes; modify the template during a traversing of the template, including: on a condition that two or more nodes of a tier have a common feature, aggregating the two or more nodes associated with the tier into a cluster; and defining impact rules for representing a state of the application in response to events affecting the nodes; and generate a display of the template indicating states of the application according to the impact rules, wherein the states include at least one of an actual state or a scenario state, wherein the scenario state is displayed in response to a simulated change to the application.