"Addressed" is a strong way of putting it. They are undoubtedly better --this is undeniable. They are still not what I would call a quality firearm, more in line with Kel Tec if not slightly worse than that. So experiences can be expected to vary greatly depending on the gun, and there are still a lot of cut corners.
I've an original R51, and have examined not one, not two, but three new versions. The 1.0's were sub-Ivhesk Soviet quality; it's a miracle mine runs at all, frankly, and the corporation should have been far more embarrassed than they were. The new ones have few(er) crude tool marks, the bolt in particular is much nicer, but there's still lot of rough edges internally, parts that don't fit great, cheap design/fabrication choices, that simply aren't seen anywhere but the very bottom-end price bracket (which as you said, the R51 is very close to occupying; whether it is a good deal or not has nothing to do with whether it is a quality firearm or not). Dirty grease, but not gobs of dirty grease with metal shavings. Peening on the cam surfaces instead of galling/gouging. Trigger is only unacceptably wobbly instead of laughably loose. Mags now feel merely cheap instead of flimsy. The exterior smoothing/dehorning is fairly nice for a gun of this (or any) price, though the Remington bead blast finish isn't my fav. In short, the primary things the R51 has going for it are novelty & lack of competition at an unimposing price point; that's a very short-lived game in gun marketing, and Remington needs to do much better --like with their 1911s-- if they want to keep selling these.
