Botvinnik (2885 in 1945) was stronger than Petrosian (2796 in 1962).
http://www.chessmetrics.com/cm/CM2/PlayerProfile.asp?Params=199510SSSSS3S100509000000111000000000000010100
http://www.chessmetrics.com/cm/CM2/PlayerProfile.asp?Params=199510SSSSS3S015154000000111000000000000010100
Botvinnik was with two intermezzos (Smyslov 1957-1958 and Tal 1960-1961) the World Champion from 1948 until he was dethroned by Petrosian in 1963. Petrosian lost his title in the next match in 1969 against Spassky.
Botvinnik was also more influential, as he headed the Botvinnik school of chess that produced Karpov and Kasparov.
The style of Petrosian is distinctive. Petrosian himself acknowledged he was most influenced by "My System" and "Chess Praxis" by Nimzovich.
I have been going through some petrosian games and I am really impressed. what are your guys thoughts over my comment? do you think petrosian was more influential than botvinnik?