Mercedes' design has a very American flavour lately. I agree with you, but I really don't know whether it's Chrysler's influence. I know it happened in the same time DB and Chrysler came together, but it could also be a trend MB saw necessary to follow, since the American market is such an important one. To be honest I don't directly connect MB's design to Chrysler's. It's just that Chrysler design very American cars with all the aspects that a typical American car should have. IMO of course.
MB is trying too hard to go back to the glorious era of the 80's where some of the best MB designs were presented, but there's still this annoying american taste. The cars lost there German-ness in design. Maybe also their "Purity" like you say.

The pics that you posted are from an era where Chrysler started the whole retro wave that gave us the PT Cruiser, The new Beetle, The Mustang and lately the Camaro. It was a very influent move by Chrysler.. too bad their new concepts aren't that dominant.