I don't see it affecting vintage much at all myself, but I guess time will tell. Whatever happens, I think a lot of us have been feeling a bit meh about collecting in the last year or so, so I'm hopeful this line could shake things up a bit. I'd be perfectly happy for loose prices to tumble, I just don't see it (at least not because of these).
For all we know, they might make these and no more. I think this line works for the first 21, and it would absolutely work for the last 17, but can't see them producing all of them (madine, klaatu and the like) unless packed in with other stuff.
I have picked up the first six out of curiosity but I'm undecided on whether I will carry on collecting these because it depends on how it all plays out here on in. The price point is critical for me, if these are 'hard to get' or they start charging 20 quid each or pretending they are investment pieces, they can forget it. If Hasbro go down the route of relatively cheap, cheerful and widely available in the spirit of the originals I will be happy to go along with it.
I think you could make a good case for this having a damaging affect on the repro market and non-creative custom figures - for instance, if you were inclined to do so, why would you buy a loose vintage Leia with repro cape and pistol for 30 quid on eBay when you can get this for a tenner? The same with army building custom stormtroopers with repro blasters.