I'd love to see W Paris under 300 but I don't think that'll happen during this decade.
The current Lowest Standard Rate is 555 euros a night. The Fantastic suite (which is 32m2 btw...) is 765e / night.
I agree that Hotel Costes is here to stay for the fashionistas. Time will tell if W is suited for Europe. I see it more as a brand that would appeal to the Russian (with W St Petersburg already open) and Asian clientele. Having said that, I thoroughly enjoy W in Asia and cannot wait for W Bangkok!