After all that has been said about the matter (sorry for missing the right links) I’m starting to think seriously to Thimbleweed Park as the definitive word on Monkey Island original world (chapters 1 & 2) and its story in terms of objective meaning.
Probably there is no room for MI3a as intended by Ron after TWP appeared. Maybe this is subconsciusly wanted.
I would accept the “curse explanation” more than “it was just a dream by a kid in a theme park”.
The positive thing is that Ron has already stated that the “kid in the park” hypothesis doesn’t match with the real story/secret:
[Flirbnic] : There are a lot of theories about what the Secret of Monkey Island is…
One of them is that there are portals everywhere eg. when guybrush falls down the hole on Dinky Island, he goes through a portal to the hallway world and after Guybrush takes off LeChuck’s mask, they go through a portal to the carnival world, where the grog machine came from.
Then there is my theory that the secret is the location of Monkey Island
And there is another theory that it’s all just a dream that a little boy (Guybrush) was having while in a ride similar to the Pirates of the Caribbean thing…
Which of these is closest to the Secret of Monkey Island?
[Ron-G] : Cold, cold and cold.
One is closer than the others…but not much.
(Source)
Why not? Aren’t they meant for each other?
Guybrush : (walks away) Oh, Governor…
Elaine : (comes closer) Oh, Threepwood…
Guybrush : (comes closer) Oh, Elaine!
Elaine : (comes closer) Oh, Guybrush!
Guybrush : (comes closer) Love muffin!
Elaine : (comes closer) Sugar boots!
Guybrush : (comes closer) Honey pumpkin!
Elaine : (comes closer) Plunder bunny!
Guybrush : Kiss me!
Elaine : (turns away) No! We mustn’t!
Guybrush : What?
Elaine : Not here, where everyone can see us.
Guybrush : Why, are you ashamed of me?
Elaine : No, no, it’s not that at all… It’s just that many of these pirates have made advances toward me. And to avoid hurting their feelings, I’ve always told them that my father made me promise never to fall in love with a pirate. If they see us together, they’ll know I was lying.
Guybrush : Okay then, let’s go to your place.
Elaine : Okay.
(take some steps) But finish your trials first. I don’t want you to be… …preoccupied.Guybrush : But…
Elaine : (walks away)
Guybrush : I feel this sudden urge to complete the trials…
…quickly.
(Source: full “The Secret of Monkey Island” script)
I agree about the fact that a modern graphic style could be an important selling point today.
What does it explain? 
Just gimme. No complaints. Just freaking gimme Monkey Island, more Monkey Island. I don’t care.
GI.
MME.
I’ve thought the same thing recently…
I’ve realized that my enthusiasm for MI3a depends heavily on it following a course I’ve always just assumed it will follow…
I’ve always assumed you go to a house as a kid Guybrush (and meet kid versions of Stan, Herman, etc.) and have to figure out how to undo the curse and get back to reality (the pirate world) where you finish up defeating LeChuck and getting Big Whoop, etc.
So the very end would be similar to MI1, but on a grander scale.
The Phantom Menace didn’t lessen my love for the original Star Wars Trilogy.
Case closed. Give me MI3a.
That was a complete stand-alone trilogy, though. People who don’t like the I-III movies can just ignore them and enjoy their memory of the original trilogy, which has a fulfilling ending.
Stan’s Super Sales Sailing
You, jelly stick! BOOM!
I think that’s because it would be too obvious to start a MI3a with the same premise you ended MI2 and hold that premise throughout the game/story. That would end up as a predictable, flat story arc. Just look at MI1 and MI2 (or TWP for that matter): none of them end like you would have thought in the beginning or at least the journey in between had some unexpected twists and turns. MI3a would be no different. So in my opinion, it could very well start out as MI3 did, only there they decided to quickly jump ahead to grown Guybrush back in the “real” pirate world and end up again at the Carnival of the Damned, which is pretty flat and maybe why it disappointed so many hardcore canon MI fans.
Another question you should ask yourself: despite being happy there won’t be a MI3a most likely, let’s just assume there will be one in a few years… would you NOT play it? Would you resist just to keep your younger self happy? Or would go “screw you, younger me! Grow up!” and play the game you wanted so long. You survived playing TWP too, didn’t you?
My 2 cents on the real secret: The pinnacle of meta
Note that it doesn’t exclude the possibility that Ron reuses some ideas, including what he had in mind for MI3a.
Also be aware of the historical reality when either MI or MI2 was made: at that time, there was no plan for a sequel let alone a trilogy! Ron could have had a story line in his head, just in case the game sold well and Lucasarts would be ok to do more of these (with him), but unless you have the Voodoo Lady’s clearvoyance powers, you’d better close every game such that the story can exist without a sequel.
The only ones to “blame” for not having MI3a instead of MI3, are Ron leaving Lucasarts and all you guilt-absolved pirating kids back then !
One possible storyline for MI3a -in my mind- could have been a full game where you play Guybrush as a kid in England in the 1970s or 1980s, who’s got a crush on a girl at school, Elaine - who’s kind of the bully/popular kid. The school principal is a well-rounded black woman. Guybrush’s dad needs a new car (hello Stan!), their house burns down in a series of events triggered by his brother Chuck (the insurance agent shows up, hello Stan!), …
And then maybe, just maybe, in the end you do return to the old Caribbean (travel agency: hello Stan!), somehow break the curse and be transported back to the MI1/MI2 universe.
Probably you would be disappointed when all of that would turn out to be just a Voodoo curse, because you enjoyed all the wonderful puzzles, dialogue and new characters you will miss (Guybrush’s dog, Spiffy!).
Yes, they are. But, it has been an element of the humor that they just couldn’t get together.
Not entirely, because the actor of Anakin’s ghost at the end of The Return of the Jedi has been replaced by the actor from the episodes II and III. Though, all in all, I agree with you.
Interestingly, Ron tells in the commentary of the Special Edition that everything would be explained fully in the ending of MI 2. Of course he can also be joking, but who knows…
Just watch the first few seconds of this video in order to listen to what I’m refering to (sorry that I hadn’t found a video with a better audio quality!):
Ron stated in an interview (don’t know which) that Elaine and Guybrush shouldn’t marry.
What does it not explain? 
It explains the whole fantasy universe of ghosts, voodoo ladies, the root beer machines, the weird consistence of the Grog, a lot of childish behavior of Guybrush, a rubber chicken with a pulley…
Really? For me It was obvious that Guybrush get Elaine and defeat LeChuck. Each other end would be a surprise.
I have read that too. But personally I like the romance between Guybrush and Elaine.
I hated the marriage.
During the whole Monkey Island 2 Elaine makes nothing but remark how her story with Guybrush was a waste of time. Come on, she even wrote best selling books about how a lousy partner he was. I loved how you could feel the dread she felt for her ex boyfriend, and how helpless Guybrush was.
And then, out of the blue, in the first minute of the third chapter she says to LeChuck that Guybrush is her only love? Come on!
Ok, maybe that one was a bit predictable, but it is excused since it is the first game and doesn’t have to meet certain expectations. You surely did not predict insult swordfighting, three-headed monkeys, vegetarian cannibals,… before playing that game (or after the first few minutes of gameplay)?
To quote my favourite writer “He who is certain he knows the ending of things when he is only beginning them is either extremely wise or extremely foolish; no matter which is true, he is certainly an unhappy man, for he has put a knife in the heart of wonder.”
I would say that it’s unlikely that I wound’t play it, but I might be extremely cautious before deciding what to do. For example, I might wait for some reviews and opinions before buying the game. Screwing up a sequel is quite easy.
I’m technically able to do that, yes. 
I don’t think that comparing Monkey Island with TWP would be fair, because I don’t care about TWP as much as I care about a childhood memory. For example, I never liked very much the whole story of TWP, but that didn’t prevent me for completing the game and enjoying it, because I didn’t have the same expectations that I would have about MI3a.
Yes, I’ve seen that screenshot somewhere else and I intentionally didn’t comment in that thread because I don’t feel comfortable hypothesizing that (spoiler coming about a possible plot twist in Monkey Island) Ron used the overused “it’s just an illusion / dream / fantasy” card.
Actually, Ron planned it as a trilogy before M1 production ended:
Moreover, after I played MI2, I perceived it as a clear trilogy, because in my opinion the ending of MI2 leaves a lot of topics open.
Oh yes, I understand now.
I remember that commentary. Trust me, that’s sarcasm.
I know, but who knows how Ron would make their story evolve? Between MI1 and MI2 they spent some time together and Elaine realized that Guybrush was an idiot, but while it’s unlikely that she would marry him for love, it would be coherent with their relationship if she would marry him for pity.
(Source)
I laughed a lot when I discovered that book. 
There is no third chapter.
Not only that, don’t forget there are also a lot of romance books by Melanie Leary which make Guybrush disgusted since he also says “Why would she write this?” for one of them, plus the explicit “Next to nothing”, I always supposed they were some kind of joke about Elaine’s need to vent off her need for romance while she was with Guybrush
Sure, but still he could not have known at finishing either game that he would have the chance to make the sequel(s). So while in his head (or even on paper), he had the story laid out, it is common practice to give every episode some kind of closure, just in case…