I don't think they copied the copies.
I think the new reprints are copies of originals.
Totally they are. Sorry I didn't realise that wasn't well known. All three "reprints" are digital scans of copies of the print runs of the originals that GW had "lying around". They were then cleaned up a bit on the computer and the resulting (rather large raster images of each page) whacked over to China for printing.
My reprint is certainly not as clear or crisp or as light as the originals.
They will certainly have lost some nuance. All the halftone and so forth for instance, that can end up being "urgh" when combined with excessive digital compression. And as mentioned I can clearly see the borders were not the same black pass as some of the text so they were presumably on the other plates for each page.
My copy of the John Blanche book from Wombat I think is too dark on the pictures and that is a "print on demand". It's hard to know how many inks they use in the commercial systems, it certainly doesn't have to just be CYMK in a printer, commercial printers sometimes have additional inks to help with quirky colours.
I don't imagine they had the original plates or the new ones would be as nice as the originals.
I can't imagine they made new plates as that would cost a bomb and they would be as nice as the originals.
The printing plates will be long gone - the printer will have had them anyway, probably with an agreement to retain for a while for reprints. I expect given digital printing (ie posh laser printing) is run of the mill (haha) it'll just be done like that.
The originals are much better quality in terms of production values, it is just do you want a beat up original or a brand new lower resolution version?
Well you have both, that's the answer
Ideally a few copies of each just to make sure you're well covered no matter which room in the house you re in! Then again I quite like repairing the spines on old books and having patched up three of four copies of various RoC books for people over the years it can be quite fun to make them "reasonable again". Bit of wear and tear only adds to the charm!