Here is what I have suspected since ages: at some point FD plans to replace the current system with a 'handcrafted mission chain' system. The 'mission DLC leak' would be one way. It would explain why there is no alliance ranking. It would be easy to copy&paste the current system with ranks for the alliance, but this way even veteran players will have at least one campaign left to do when it is released.I get that, and I know we're not "King of the Empire", or whatever. However, as Deejayeff145 points out, obtaining the top of the rank structure is just anti-climactic.
In any case, the current system is nonsense. Not much more to say on that front.