Interesting that it was an option as to be honest it could actually be a bit of a pain in the arse in the real Missed Approach world which was often 'climb straight ahead, maintain 3000' or something similar.
In the Boeing 777 QRH section showing various manoeuvres for the go-around the procedure shows, at 400'RA, 'Select or verify roll mode'.
Arguments could be made for automatic or non-automatic LNAV engagement but in a perfect world at 400' the appropriate mode should be selected.
The problem arises, in my view, because most go-arounds often take the crew by surprise unless previously briefed for the possibility due to inclement weather. For this reason, and I see this regularly during conversion courses, go-arounds are generally well flown when expected and less well flown when a crew is taken by surprise.
When I was flying I clearly recall the startle effect when receiving an ATC instruction to go-around on a least two occasions when I least expected it!