A wireless communication network receives packet data transmissions from a mobile station, tracks the occurrence of retransmission requests sent to the mobile station responsive thereto, and modifies the radio link assignments for the mobile station based at least in part on said tracking. For example, a base station controller may be configured to manage the active set of a mobile station based on the number and/or frequency of NACK messages sent by the radio base stations in the mobile station's active set(s) responsive to packet data transmissions from the mobile station. The ACK/NACK response of a radio base station to mobile station transmissions may be used to detect link imbalance, identify poor reverse link channels, etc. The base station controller can add or change radio links based on the ACK/NACK response to improve reverse link performance, trigger voice call handoff, correct link imbalance, etc.