Yes, you are right that the spin bowling line in Pakistan is a bit weak. But I think Pakistan team is very strong. They are leading in all aspects but they are lagging behind in one aspect. If they can make their spin bowling a little stronger then I think they will be a strong team in all aspects.
If they want to beat pig-4 teams on a regular basis, then they need to have a well balanced team. And at this point, spin should be their biggest worry (doesn't mean that they are perfect in other departments). Also, they need to focus on the middle order. Top order batsmen such as Babar are getting the runs, but middle order is not being consistent. For now, middle order is low priority. They need to focus on spin bowling, if they want to perform well against the Asian teams such as India and Sri Lanka.