Theres no problem with you disagreeing with me, I am not an extremist I won't threaten to blow you up
. I respect your opinion.
Now all I am giving is a very rough suggestion, there are numerous problems with my idea as their are with any others. If such a big decision like breaking up Afghanistan is taken, then it wont be properly addressed by some guy typing ideas on his PC. It will be discussed with local authorities and all neighboring countries and will take years of planning to properly bring up a plan.
You say that after the US leaves, the the population will not go back to grabbing each others throats, may be they will , may be they won't, I am not a prophet I can't predict the future, but recent history suggests that a similar thing can take place. A tribal war will start up in the name of religion, ethnicity, etc. but then like all wars it will become a war of power and cash, where war lords will fight to get the biggest slice of the cake. The ANA in its current state is not capable of keeping Afghanistan in check and I doubt it will be ready by 2015. The ANA are amde up of Pashtuns, Hazaras, Uzbeks. They are all humans they all have the same fore fathers who lived and fought in the tribal wars, many of them probably lost family members to these wars, who is to say that they won't join the tribal wars themselves. As far as I know the ANA hugely lacks unity, they don't really have that much respect for faith in Hamid Karzai.
One can question how to control the independant states if Afghanistan is divided, clearly a very strong govt will be needed in all of them, preferably a strong dictator who rules with an iron hand and can keep things in their states in check.