SU5 introduced the ability to mimic adverse yaw. This is probably where the lack of stability on the approach has come from - it’s a very blunt implementation of it, and with the inability to adjust for speed (the sim ‘takes care of it for you’) it can only be seen as a starting point. As a developer, we have very little control over it, certainly less than in FSX!
Smoothness of the rudder appears also to be an issue, as the ability to fly a coordinated turn is nowhere near as easy in this sim as in real life.
Adverse yaw was one of the most-requested flight dynamic improvements, yet it appears little thought has been given to correct implementation or other aspects of the flight dynamics which are tied in with it.