ZAF, i really dont think u can back u arguemnts..
Serie A is more physical and all what uw ant, but as Denco said, when someone is really skilled, there is no physical or whatever thing that can do much for u to stop him.
Ronaldinho have the skill to pierce the defenses of iNter, JUve and MIlan. IN one of his days there is not much that any of those 3 defenses can do.
If he can beat this teams... he can easily beat any team in serie A with his skills.
The only factor that would stop him is that.... he is very pleased in barcelona... and in Serie A he would not be that happy.
thats the only reason.
There are some players that dont perform well in some leagues, but when u are at the level of a Ronaldinho or a Zidane, adversity is not that important.