Putting plastic on an older rifle won't make the weapon any better. Putting RIS systems on older rifles won't make them any more effective. It's what you put on those rails that makes a difference. Putting plastic on an AK just makes it lighter, not more accurate or more powerful. So yes, it handles slightly better, but it's still the same weapon. Look at the M14. It was designed as a 7.62x51mm battle rifle to be issued to front-line troops. It didn't see much action with the army, since it was replaced in 1964; slightly before the US saw major combat in Vietnam. The USMC continued using it until 1967. It saw limited use as a sniper rifle under the nomenclature of the M21, though, we know that it wasn't designed with that role in mind. Modern M14s are still the same rifle, but they just added a crap-ton of rails, adjustable stock and plastic. It's still an M14, but it's now just being used as a DMR or sniper rifle. Plus, the original weighed 9.8 lbs unloaded, the M14 EBR weighs 11.24 lbs unloaded, and the M39 EMR weighs 16.5 lbs unloaded. It's gotten heavier so it's a good thing we no longer issue it to grunts, it weighs as much as an M249 SAW! Did the rails and plastic improve the weapon? Not that I can see. Rail's and plastic didn't make it better; modern scopes, grips, flashlights and laser systems did.
On topic: This weapon is actually beginning to grow on me. I recently found out that the Australian military has deployed these in Afghanistan. Sweet...