no it wouldn't make any sense. you people seem to forget Sony has done the slim for every single gaming machine they put out.
Ps1 had a slim, ps2 had a slim and those lead the market with a gap bigger than the wii's total sales. so they need to have price cuts and a redesign to huh?
ps3 slim was a "duh, shit was bound to happen" moment.
all M$ need is a price cut. a slim would be just as blatant a rip-off as Sony's motion dildos.