I downloaded 4.0.1 last night and at home I could still cover the antenna and the signal would drop a bit, but at work, I cant reproduce it. I know at work I only have an Edge connection and at home 3G, so maybe that is why, but I cant help thinking that perhaps the "fix" is simply a cover up?
To be honest, it never made much difference to me - I dont really use my iPhone for calls anyway, its more like my life organiser with the ability to make calls. I do text a lot though, so the phone features are not completly devoid.
Lets see what the press release has to say today - hopefully I'll get a free bumper out of it :)