[AndreaDraco83]

Oh, obviously Jane would have to re-write them to set the pace of the plot accordingly, but all the tension, the Spannung, the charm is already here.

Anyway, after one hour and a half, I finally found what I was looking for. Once again from Wikipedia:

None of the games explicitly reveal the "Secret of Monkey Island" (although creator Ron Gilbert has stated that the secret was not revealed in any of the games, and that the true secret would be revealed if he got to work on the fifth entry in the series). LeChuck himself, when asked in the second and third games, refuses to answer the question; Guybrush can eventually prod LeChuck to confess that he does not know what the secret is.

There are many hypotheses popular among players, and at least one case can be made from each game in the series.

Spoiler:

One of these hypotheses states that the bizarre revelation at the end of MI2 is the true secret of Monkey Island (again, Ron Gilbert has confirmed that the secret is yet to be discovered, in an interview with GameSpot). The fact that it was debunked in CMI, the hypothesis states, is merely a retcon by the new development team after Ron Gilbert's departure. Elements in the closing scenes of MI2 seem to support this hypothesis, as do certain comments of pirates in the insult swordfighting section of the first game, asking Guybrush to "play along".

Members of the CMI team (many of whom were also part of the MI2 team) claimed at one point that they knew what the original secret was: that the storyline of the games was simply the fantasy of a child. Gilbert, however, has contradicted this in various interviews, saying that he never told anyone what the true secret of Monkey Island is.

The references of the aformentioned statements can be found at this link, which feature an audio interview with Gilbert himself.