With the recent update to Battlelog in preparation for Battlefield 4, all of the symbols and artwork needed for the game have been inputted, and one of those is all of the ranks. I talked about what I thought the ranks would be like in a previous post, and it seems now that they have kept the ranking system very similar to BF3, but there are differences.
The low down:
There are only 100 ranks, and Colonel is the highest, but there are no numbered colonels as in BF3.
I am guessing that it will take more time for each rank, especially compared to the low ranks from BF3 and their counterparts in BF4. The Beta showed us that it did take a significant amount of time to rank up even the lowest levels, with the many ways to score included. Although, there is speculation that those numbers were placeholders, as they wanted to see how fast people ranked up. They most likely have changed it in the final release.
With this, we do not have information on the numbers needed to get each rank. Since it is likely it will be about the same amount of playing time as BF3 to reach the top rank, we can conclude that they will make every rank a little longer to get through.
Another bit of info, to be considered for commander, you have to have reached rank 10, so that may be an important milestone.
DICE has a vested interest in making this formula perfect, as there is a fine line between keeping the game interesting by making rank ups rewarding, but also the longevity of the game, and how they can have people stick around. I am very interested to see how they pull this off.