Interestingly, this wasn't a new requirement, at least in terms of the intended role of this type of fighter. Since the 1970s, the PAF had always sought a new dedicated attack -- and later, strike -- asset, but it never panned out.
It first aimed for (and almost got) 114 A-7s, but the US didn't want to send it while Pakistan still had an active nuclear weapons project. Back then, the US fear was that the PAF would literally arm the A-7s with nuclear payloads, and the A-7 had cutting-edge gear at the time to enable guided deliveries. In fact, there may have been a concern that the PAF already had warheads (via the Chinese) and was just seeking a delivery platform
@SQ8
In the early 1980s, it looked at the Jaguar, but it was too expensive and instead opted for the A-5. It then gave the M2K another look in the late 1980s, but the PAF preferred acquiring more F-16s (understandably so).
In the 1990s, the PAF looked at the M2K-5 and the Tornado. The latter was the perfect strike platform, but it was too specialized as the PAF now needed a new multi-role fighter in lieu of the F-16s. It picked the M2K-5, but couldn't close the deal to internal Pakistani turmoil at the time. IMO, a Tornado deal would've happened if the Peace Gate III/IV F-16s were delivered.
Basically, the PAF was amenable to a twin-engine fighter, especially for the strike role, provided one was actually available and affordable. Unlike the Tornado, the Kaan offers a multi-role capability, but I'd reckon the PAF will primarily use it for the strike role (assuming it succeeds in getting it).
The PAF's aiming for a 'next-gen' hi/lo mix consisting of the Kaan and J-10CE, with the JF-17B/Block-3 filling gaps and niche roles. Moreover, the availability of increasingly advanced drones, especially flying-wing UCAVs, may see the PAF reduce the number of manned fighters in the long-term too.