My Afghan strategy in brief: continuing to spend time and resources attempting to modify Afghan society [a kind word], whether in its cultural, political or military manifestations, is stupid, a waste of effort.
Consequences of above determination: let them have at it. If the Afghan army [another kind word] is still incapable of defending itself, too bad. If they can't fight for what they believe in maybe that's because they don't believe in anything worth fighting for. Either way, we can't do it for them.
Consequences of the consequences: retreat looks bad, even if it makes sense - the short term upside of getting the fuck out may not be worth the long term downside of just getting the fuck out - so maybe a retreat that isn't really a retreat? Annex a part of Afghanistan [hell, we've earned it - some prize!] for purposes of maintaining a large military base, stop all COIN operations [COIN is a waste of time if you can't change underlying culture] and from this bastion we continue to 'support' anything worth supporting and Predator the crap out of anyone that pisses us off. Concurrent with that, figure out some way to seal the border between Afghanistan and Pakistan [oh, boy] which is the only way to lop off the head of the Taliban serpent [I guess though if you could do that the first part would be unnecessary? No, I wouldn't say that...].
Or you could just get the fuck out.