[Leadership] Trading followers of another cohort?

[Yael]

I know that the very fact that a cohort is granted by the Leadership feat is pretty strong already, but how would be if you could get another cohort, completely replacing your followers, but obviously nerfing both cohorts. Maybe replacing the clause that states that the cohort must be at least two levels lower than the character's ECL with the Leadership feat, with a clause that states that both followers must be at least three levels below the character's ECL with the Leadership feat.

Or maybe, by removing the followers, making both cohorts to have a level difference of 1 or 2, after applying the -2 from your ECL.

[OldTrees1]

Existing options/precedents:
1) Take Leadership twice. (Aka: Leadership & Undead Leadership)
2) Be a Thrallherd

In general, a cohort that is used to increase the optimization of the PC will be a strong-overpowered usage of the Leadership feat. A second such cohort is worth much more than the followers. However some cohorts are selected as a way to mechanically represent a concept. These cohorts tend to be stronger than the sum of the followers but not in an unbalancing way.