CX options from HKG (or points beyond) to BOS are sure tough. YYZ would be a natural gateway for us BOS folks, and it's OK outbound, but on the return the connection doesn't work, requiring an overnight stop in YYZ. JFK has the problem you experienced -- risk of a missed last connection -- as well as lousy one-class Eagle service. LAX and SFO timing don't work either, last time I checked, though once I managed to fly HKG-SFO-BOS with a reasonable ~120 minute connection at SFO.