I think that buffer bloat is a red herring here, and suspect that QoS is the real challenge. This is something we are actively working with Pace on, the 4111N doesn't currently support upstream ACK prioritization, and that can impair performance during times of upstream saturation with some applications.
agreed.. maybe it's not really 'bufferbloat' if it's on the CPE. but since there is an upload buffer presumably for performance reasons with DSL, then yes, control packets should be brought to the front of the queue. does that sound right? (this is purely curiosity)
FYI, i just got an AT&T-provisioned Pace 5268AC for Sonic FTTN and it is suffering the same latency issues during upstream saturation as the Pace 4111N did with Fusion.