I don't know if there will be a huge change. As it is now, most people from Brazil who go to Disney are really wealthy. And those have no trouble getting a visa. The visa is difficult (and expensive) to get for the average person who can afford a trip every few years unlike the wealthy ones who can go whenever.
As for the tour groups, not sure that will change. The vast majority who go with tour groups are teenagers. Everyone who can afford it (no need to be that wealthy), saves money to do something special for their kids when they turn 15. For many, that is a trip to Disney. Since most parents can't afford or don't want to go with their kids...or the kids rather go on their own with friends, they send them with a tour guide.
Also, when you go with a tour group, it's much easier to get a visa.
If he makes this announcement, it will help, in my opinion, people who are not filthy rich but can afford trips. People who don't go with tour groups, people who live too far away from the only 4 cities that are able to give you a visa, that you have to be there in PERSON, by the way, you can't just mail something in like in the US. Also, the closest city for me has a 3 month wait. So if I didn't have a visa, and wanted to go to the US by the end of the year, I wouldn't be able to start booking anything until late march, when I would finally be receiving my visa in the mail after going there in person.
So yes, maybe the number of tourists will increase, but that doesn't mean all tour groups and certainly doesn't mean they will all go to Disney. I'd say most people I know never even want to set foot in there. They have no interest in ever going to Disney.
But I think the biggest change is that it will be a smoother, less expensive and time consuming process for those who already go...maybe they'll go more often or stay a bit longer...or just spend the money they'll be saving shopping more.
I don't think it will be anything drastic either, maybe they will make it easier for those who already had a visa before, maybe the renewal process will be easier. Maybe they will allow some people to request a visa via a form they mail in, like it used to be many, many years ago...and like it is in the US.
It could be they will finally honor the "reciprocity" they claim to have with Brazil and Brazil has with the US. As in, if the US requires us to have a visa to enter the US, we require Americans to have a visa to come to Brazil.
Brazil lets Americans get a visa like I described above, mailing in some papers. Whereas the US requires that you be present in a consulate, get fingerprinted, interviewed, your taxes, assets and all your bank accounts looked at and analyzed (not always, but sometimes). So the process is quite different and not very reciprocal.