This is great point which you mentioned about Afghanistan cricket team lineup. Their team relies on few key batters which means they win big or lose big. Having too many all rounders as you mentioned can be problem because they are not as good at batting or bowling as specialists which makes team less consistent. In contrast Pakistan with more dedicated batsmen has more stable and reliable foundation. Your analysis is good for Afghanistan to become top team they will need to find better balance in their squad and rely less on all rounders.
Are you implying that Afghanistan is overdependent on a few players? That is quite surprising, because Afghan players are popular in franchise T20 leagues. Therefore I would expect them to have a balanced team, at least in the T20 format. But at the same time, there are a few things which are beyond their control. As a result of the civil war, home matches are being hosted in the United Arab Emirates. Grass-root coaching is another area which is impacted, as foreigners don't want to travel to Afghanistan.