I think it could really take away sales of the aluminum XJ, which is an awesome car. The XJ will need the rumored, more powerful V-8 from the next aluminum XK and a new front bumper by the time the next S-Type comes. I think a front bumper like that of an S-Type R would be great.
It could be a great car, especially if Jaguar offered a V8 version with a manual transmission. I think it would draw buyers away from BMW, Audi, and Mercedes, especailly if Jaguar really beefed up performance of the non R spec versions. The grill could stand to be smaller, and replace the mesh with vertical slats like the old ones had. The chicken wire looks like a last minute afterthought.
I think an aluminum S-Type wagon would be a good idea, but it shouldn't be sold in America though. Wagons are becoming more popular here, but not like in Europe.