After today, in my mind if you are a 125k+/yr international flyer (heck, 100k!) that's primarily in Y, there is absolutely no reason to stay with Delta aside from a 125% mile bonus...for anyone doing that much flying in Y, I'd be avoiding Delta just so I could get a few trips in Y at a reasonable price.

After today, if Delta does not lower PMU usage to K+ fares, they will be very non-competitive with their counterparts.