And that being said, sometimes I think it's a good strategy to book two one-way awards rather than a round-trip so that you can grab those seats not a moment too late at 330 days out. However, one-way overseas awards don't provide the luxury of getting stopovers like round-trip awards do.
There's another factor, far less predictable. The partners (QF for AA, and AC, SQ, NZ, etc for UA) release their 1st and biz class award seats on a very different schedule, which I don't understand at all--sometimes just one seat at a time. Occasionally, you can luck-out when somebody like ANA suddenly announces a new route like NRT-SJC and then suddenly there's award seats available all over the calendar until they get swooped up.
Do remember that not all airlines are made equal. For example, IMO 14 hrs or even 2 minutes coach travel in a fully packed UA 747-400 is cruel & unusual punishment at an industry low of 17" seat width, no seat back IFE and no complimentary booze. QF's Airbus 380coach offers 18.1" seat width, seat back IFE, complimentary booze...and a snack bar. And then there's coach on Thai Airways and the like, which are almost preferable over UA's bizfirst, save the inability to lie flat.
AA's pretty nice but at 330 days out, strange things do happen. I had an AA award booked on an HA route SJC-HNL-SYD about 330 days out. About three months later, the SJC-HNL flight ceased to exist and I was automatically booked on SJC-OGG and then OGG-HNL-SYD except that the SJC-OGG was scheduled to land in OGG a few minutes after the OGG-HNL flight was scheduled to depart. AA then wanted to dock me more payment because now there's an overnight stopover in HNL so that instead of one-way SJC-SYD, there's two one-ways SJC-HNL and HNL-SYD. The complications got crazier with AA keeping my original schedule but having me go SFO-HNL-SYD. When I wanted to get back to a SJC-SYD route, they wanted to charge a destination change fee.