Recently, network coding has gained much popularity and several practical routing schemes have been proposed for wireless mesh networks that exploit interflow network coding for improved throughput. However, the evaluation of these protocols either assumed simple topologies and traffic patterns such as opposite flows along a single chain, or small, dense networks which have ample overhearing of each other's transmissions in addition to many overlapping flows. In this paper, we seek to answer the fundamental question: how much performance benefit from network coding can be expected for general traffic patterns in a moderate-sized wireless mesh network? We approach this question via an empirical study of both coordinated and opportunistic coding based protocols subject to general traffic patterns. Our study shows the performance benefits under both types of coding for general traffic patterns are extremely limited. We then analyze and uncover fundamental reasons for the limited performance benefits.