I'd be okay with this if it was in the game and like others said, updated with each patch via community effort. Not everyone even realizes there /is/ an optimal rotation, or even a proper rotation at all to some classes, so having a place to start that they're forced to see when selecting the job and that covers each step of their progression would be handy. Hell. Even just a 1-50 rotation explanation, that again is updated because SE borks that with each expansion, would go a long way to helping the 1-2-3 or 1-1-1 spam we've all seen in dungeons.

The issue as others people have said however, is that someone /needs/ to keep it updated. And I don't trust SE to do that.