Asthetically...I think that a 757 with those blended winglets is gonna look...dumb.
BUT...stop the presses and hold back on the flaming, my winglet-obsessed associates...
Getting more bang for your buck is also a sound business practice. If this is going to cause the 757s to save more fuel in the long run, and allow them to stay in fleets longer, then yeah, by all means, go for it. I can get used to them with winglets, no problem. I'm just not gonna be all over the board saying "Man, winglets on a 757 are gonna suck the big one!" It's all about economics...not looks.
Save the whales...for dinner!!!