If you want a new rifle just because you like it, go for it. But if you want your new rifle to do something your current rifle doesn't, driving the same bullet faster doesn't strike me a much of an advantage. The only advantage that the .270 WSM has over the .270 Winchester is a slightly flatter trajectory. The question is, can you make use of the difference in the field? I couldn't.
IMHO, the .270 Winchester is a better general purpose hunting cartridge than the .308. I like the .308 and have a couple of them, a target rifle and a gas gun, but where it shines as a game cartridge is when chambered in a short light carbine. Loaded with a good 150 gr bullet like the TTSX, it will get 2700 or a little better from a 20" barrel, which is the original .30/06 ballistics which Stewart Edward White and Teddy Roosevelt took to Africa a century ago. It killed game then, it will kill game now. WhyNot's wife packs a nifty little Ruger 77 RSI, and I'm sure he could provide a litany of success she's had with it.