i think thinking they changed to groovess due to schumi is abit far fetched, the only rule they changed due to him was the point scheme! and thats more to do with his sheep contract he had for his team mate!
it was to slow the cars cornering down which the engineers went around with developing aero to compensate for lack of mech grip by creating more aero grip
The only rule? Perhaps I am a little confused, the way I saw it was they changed a lot more. I felt they changed qualifying to try and stop Schumi from eclipsing Senna's record. They changed the tyre rules after France 2004 where Michael stopped for fuel and tyres every 3 laps and still won.
I followed F1 fairly closely when I was in the UK, I read Autosport, F1-Racing and that one magazine Bernie and Max started to air a bit of dirty laundry, can't remember the name now, edited by Nigel Mansell, anyway I used to read internet articles and I was even that much of an F1 gimp I paid for a wholesale reuters news feed and got sent every newspaper article around the world that had the word F1 in it. Yeah I had no life, my point is, my gut feeling was they did absolutely everything they could to curb Schumi's talent in the effort to preserve television ratings, without being too obvious. I even felt they changed the technical regulations to make the cars more mechanical reliant instead of driver input, further reducing Schumi's impact....
My 2cp...