DOCSIS 3.1 will resolve many of the inefficiencies inherent in DOCSIS. It is, after all, still data being sent in MPEG 2 framing.
The FEC isn't that heavy, especially when compared with interleaved xDSL.
The coaxial drop is a trump card over xDSL-based solutions, however it's a choke point when using remote PHY or BDF/BDR.
Remote PHY and/or BDF/BDR might be on the radar at some point, however there is no urgent need right now. Essentially moving the line cards out into the street might be how things go eventually but it's a way away. It is, however, a consideration for the future for sure, and VM in common with many others already use BDR.
http://www.cisco.com/c/dam/en/us/sol...pman_paper.pdf
For those who want more discussion on this. 10Gb-capable XGPON has been tested and works well.