Yeah but the KF-21 is already a finished platform,it works perfectly and can be upgraded.
The KAAN only has one prototype,nothing else,we should talk when its a finished platform,not before.
Plus we need to consider geopolitical facts, TuAF conducts cross-border operations on regular basis, and sometimes attempt to do far fetched one (Libya), operating bases in Libya - Somalia, and KAAN has been built based on certain requirements based on previous experience and upcoming threats or rivals. KF21 was evaluated and hasn't seemed to fit our requirements ie. not introducing a remarkable leap in capabilities and not answering what TuAF typically needs. I am not getting to the last point where how our decision and plan makers suck at seeing what's at the corner, or experts in being sanctioned out of blue.
Korea on the other hand had been reluctant in modifying the platform for customer needs, the focused on certain facts, keeping it simple - straightforward and answering what their airforce needs in given timeplan to replace the aging fleet with a 4+/4.5 gen fighter. And here we must admit the fact that, they planned something as is and adhered to it, both from financial and acquisition point of view.
We can't even go 1-to-1 comparison between respective airforces, let alone the fighter themselves. The discussion or comparison itself is pointless.