The modernized slide has slanted serrations, including a front cocking serration, new sights, and a threaded barrel with an optional thread protector. The front part of the slide is also smoothed, and there are some structural improvements that will carry over into the classic version as well.
The current model has a fixed trigger, although right behind the trigger is a hollow box that can probably be modified by a clever builder. I don't really like the concept of paper springs, because they'd wear out pretty easily.
The paper springs don't wear out if they're made in a precise way and are more than 1, they stay for a lot. And anyway who would press the trigger like if he's in a game. Anyway great model. What other models are you planning after this?
I have the beginnings of a new AK receiver in the works. My intention is to make an AKS-74U, but I might as well also use those parts for an AK-74(M) or a new AKM. There is no timetable for it, though.