I bitched and whined about Google Flight service being useless for searching for long business class flights with a change in them, because it would assume you were fine with the shorter leg being in economy -- even if the shorter leg ended up being 7 hours long. I did eventually get one of their PMs on LinkedIn to apparently take it seriously, but I note it's still very broken on their site putting in a Vancouver to Bangkok flight (10hr in J YVR-NRT, 7hr in Y NRT-BKK)