I don't know. Whatever You like, but I prefer the original look over the new one actually.
Maybe just a new, walnut grips and better quality magazines...other than that...ohh..well.
It's definitely a little interesting to see people's different ideas about what constitutes an improvement over the factory configuration.
I do use the same sear in my guns, and almost any quality extractor is going to be an improvement over the Norinco one (assuming it gets tuned correctly during the build process, obviously).
Correctly fitted by a skilled builder, most of the parts on that list could definitely be an improvement over a Norinco's factory parts.
Poorly fitted, on the other hand, or dropped in with no fitting at all, they would probably combine to reduce reliability. But that's life with 1911s...they are not for people who want to swap parts. They are for people prepared to put the time in to understand the system.
Unfortunately the massive availability of various parts for the 1911 means it's become a gun that is very popular with people who like to swap parts.
I would argue that that is probably 50% of the reason for its reputation as an unreliable handgun.
Of the remaining 50%, I would guess most of it is shared between, say, Taurus, ParaOrdnance, Auto Ordnance...well, this list could get pretty long.