I never saw Pele play. The only way I have of properly judging the situation is to compare Maradona with the long line of worlds best who came after: Gullit, Ronaldo, Zidane, Ronaldhino, and now Messi. Maradona, like those who followed, was an unbelievable player...as anyone can see from footage. Unlike those who came after he did what he did at a time when players with magical skill were an endangered, hunted species. Messi for one would barely have made it to the 18 yard box in that period. He'd have been a bit like George Best - having great 5-10 minute spells in games that saw him sliced in two for the rest of the match. Maradona actually imposed himself on the hatchet men and controlled most games he was involved in. For me, there just is no comparison to be made. Maradona was a colossus who could be a great in today's game; the reverse isn't true with Messi.
It's difficult to compare generations though wouldn't you say? I mean nowadays players run twice as far in a game as they did even in Maradonna's age, let alone going back to the Pele era and before. So saying Messi wouldn't cope then could easily be deflected to say that those players couldn't cope now. As it is, increasingly players now follow the Mourinho mould of being big, strong and very athletic, so for Messi to shine is very much against the norm. Ronaldo is much more the archetypal modern great.