"I'd imagine they are going to pee off a lot of their retailers (John Lewis, Tesco etc.) which could be very dangerous"
Hardly. By definition, dedicated retailers rarely have exclusivity on a brand product, so another few stores opening is neither here nor there. I'd guess Samsung stores won't be offering discounted products, nor will they be shifting any volume - their purpose is simply to be a better and more wide ranging showroom for Samsung's over-arching brand than can be achieved through Argos, JL, Tesco, Carphone Warehouse, PC World etc.
I doubt it will be a success, and they'll close within a year of opening, but even if it is a success, that will probably help other retailers shift Samsung kit rather than undermine them. Having said that, I'm with another commentard above: This shows Samsung's marketing department is out of control, and there's such a big budget that they don't have a clue (even by marketing standards) what to do with the money. Evidently the marketing department see this excess as a solution to the problem that the S4 is too f***ing expensive and not selling fast enough, and they've never heard of the Nexus 5 or Moto G. Peak Samsung, IMHO.