exactly.
Even I'm not really convinced about Asad. Isn't great in LOI really at the moment, doesn't home down the runs in domestic (42 is good, but it's not as good as others). But he's doing well so far and improving, so deserves to be persisted with.
Before the Sri Lanka and England series, definitely was a case to drop him, but he's come good. He's got very good test technique, which is a big thing going for him.
Taufeeq and Hafeez have worse records than him too, so it might be logical to drop them before Asad. The thing that saves them is that their openers (so you'd feel an opener would have to replace one of them), and of course Hafeez's bowling which is still pretty useful in tests (and he's not really doing bad with the bat of late). There's much more middle order talent pushing, Fawad Alam, Harris Sohail, Usman, Umar akmal, then opening. Opening prospects there's less talent out there. Jamshed probably leading at the moment, but might be better to stick with LOI and concerns with his fitness (though would play him if Taufeeq fails next series). Shehzad not really cemented his place in LOI, though a pretty good first class. Afaq is supposedly good, but haven't seen much of him. Plus Hafeez and Taufeeq are the only young seniors if you can put it that way who could guide the youngsters after Younis and Misbah is gone.
But yeah Asad should stay.