> Bigger (send) buffers are essential to achieve good power management
I do not think power management changes the picture. Buffers are required to reduce the frequency of context switchs in order to increase performance. Power management is just a not really special case where the "idle task" is taken into consideration.
The ACK-clocked and time-sensitive nature of TCP is totally at odds with the goal above. While TCP attempts to smooth throughput as much as possible, the above is about increasing burstiness in order to increase performance. Go figure.
This is the good same old "throughput versus latency" trade-off here again. Think "asynchronous, non-blocking, caches, buffers, bursts" versus... not.