There are two caveats. First, we must get a good deal on F-16s. If that is not possible, then we should steer clear of them. Second, one day F-16s are going to retire. What would replace them, if not J-10? Surely, one can not expect our JF-17 to be able to replace -16s.
Yes, but that day doesn't have to be too soon. The F-16 has tremendous upgrade potential, and can be quite a handful for most countries. (Except for the USA, they have to remain at the cutting edge all the time.)
It's not like PAF or IAF is entering an all 5th gen era any time soon. F-16s can be very useful to the PAF for a long time to come.