This is an old argument that everyone agrees the solution is "both are fine, provide options, and everyone can be happy". What? You're saying that's not the case and I've been vastly overestimating everyone? Damn. Well, being slightly bored waiting for the AC repair man to show up, I'll bite and type a lot of words about how I disagree with your opinion.
No.
This one is always amusing for me. James Arnold Taylor (Tidus, if you're not aware) is a good voice actor. If you dislike his voice because you dislike his voice, that's fine. Someone can come in here and say that they dislike Nolan North or Troy Baker's voices. Those are all valid opinions to have. You aren't required to like everything, but people are often confused and believe that them disliking something means that it is terrible and no one anywhere can like it (or else).
I do have a problem with is this notion that Tidus (or Final Fantasy X as a whole) is somehow terribly voiced. The vast majority of the voice acting in the English version of the game is fine. It generally had good direction and the actors were able to consistently portray their characters. The laugh scene (which seems to get so much flack even though people know it was intentional) is equally cringe-y in both Japanese and English. Some of the English was (in my opinion) leagues better than the source (Auron). You can nitpick one or the other, but propagating this myth that the localization of FFX was poorly done doesn't make any sense to me. Things can be said about Tidus' personality, but I can't imagine you're comparing blonde guy's personality to Tidus based on that trailer.
To keep on the same path, Vanille's voice actor is actually pretty good as well. The huge problem with Vanille is that she was given terrible direction, which leads us to a similar result as simply having a bad actor, but with the blame solely on SquareEnix. If they had Georgia simply be herself, it would've been much better. Instead, they wanted Vanille to have an Australian accent while still being 'Japanese'. Which, interestingly enough, means that the reason people have such disdain for Vanille is because they attempted to keep her closer to the source than the rest of the characters. I can only imagine the "bad Austrian accent" people are having a problem with the Japanese-ness they attempted to inject (since she is from Melbourne). So we blame the actor for doing a bad job, even though they just did what they were told. Seems about right.
It would be interesting if people started saying that Troy Baker was a terrible voice actor because he had to read Snow's lines. Snow may be a mess of clichés wrapped up in more clichés (and as intentional as that is), it doesn't make Baker's performance any worse. Throughout all three Final Fantasy 13 games, what was bad about Snow was what he said, not how he said it. Perhaps people do say that Baker was bad in FF13 (though I personally haven't seen much of that), but I would pin this squarely on the writing. Most people understand the character the writers were going for, but they did a poor job of it.
And to be clear, yes, there is also bad voice acting in these games. It isn't as prominent as people would try to have you believe, however, and it is tiring seeing the same nonsense parroted because it is apparently cool to hate on English actors in some circles. I can understand having a preference for one language over another, but the amount of effort some people put into hating the English voice acting is, at times, mind-boggling.
No to the first, no to the second, yes to the third. The JP track for the trailer is no better than the English track for the trailer. It, as it often does, comes down to preference. If you think the dub is awful, I'll disagree with you, but they don't have any reason not to include all languages as options. Not just because of a blu-ray disc, but because they've already show they can provide optional DLC with voice tracks. If someone buys the English version, provide the English on disc and allow them to download other languages via PSN, Live, or whatever digital distribution service is used on PC.
As mentioned before, Lightning Returns did have this as an option (console). FF13 PC had dual audio (done incorrectly, thanks to the pre-rendered scenes being rendered in both languages) and I believe FF13-2 PC also has dual audio (done correctly, since there were only a couple pre-rendered scenes in that game). It seems that they've realized that there are people who want this, so it wouldn't surprise me if they had the option in FF15.
This isn't a strange or unexpected sentiment. I understand being disappointed that they're not releasing the demo on PSN/Live (which I've previously commented about and said was fucking stupid). Looking at how the industry works, however, makes it difficult to say that this is a bad business decision. They've taken an old PSP game and remade a version of it for the new consoles, so they felt that there was a demand for the game. Since they want the game to sell, typing it to exclusive content is a pretty standard practice (that I hate). People that want an official Type-0 in English are getting the game that they want. People who are also wanting a taste of what FF15 will be are getting it. If the demo is good, they get good publicity from it. If the demo is bad, they can make changes and put out a new demo (remember, only the old demo was exclusive to the first run) and give it to everyone. Hard to say that this is a terrible decision when people have shown that it will make them more money than simply releasing a free demo. People love themselves some exclusive content.
Generally speaking, SqureEnix has been making better business decisions, but not meeting expectations players are putting onto them. They're putting the entire FF13 series on Steam, but people will complain because they're shoddy console ports (even though they're better than I would've expected, after the 360 version and terribleness that is the Crystal Tools). They patch in resolution, MSAA, and shadow options, but they didn't fix all the performance issues or they "only" did what Durante did (ignoring the fact that all Durante did was set the same values SE would need to set to achieve the same effect). There was never a chance they were going to fix all the problems in that engine just for a PC release of games, so being salty about it seems silly. If this was released at the same time the initial console versions were, I'd be pretty livid, but I never had an expectation for Final Fantasy games on the PC. I think that it is a very good sign that they attempted to deliver 60FPS and, when pressed by fans, delivered a patch with basic PC options. It shows that they have an understanding of what the PC market wants and even if they can't meet all the expectations with these ports, they may do better when they bring Final Fantasy XV to the PC.
They've also been putting most of the other Final Fantasy games on the PC. There's rumors about FF9, FF10/2 HD, and KH1.5/2.5HD coming to PC. Could you honestly say a few years ago that if someone told you that you could legally buy and play every Final Fantasy game on your PC in five years that you would believe them?
Again, it could have been done better with more time and effort, but what was given seems adequate given the circumstances. I'm rather surprised that the games aren't 30FPS locked with no graphical options.
As for the trailer, that was my thought as well. It appears as though they just replaced the voice track.
This is hilarious to me because it is the exact opposite of what I want. The reason I absolutely hate most Japanese voice actors (or the direction they're given) is because they don't seem to understand that this is not a radio drama. You don't need to be an obnoxious, exaggerated caricature. That sort of acting detracts from the game and with the most recent games, doesn't mesh well with what's actually happening on screen. The games may be science-fiction fantasy, but above that they're realistic depictions of people and not cartoons. When you start throwing around these voices that sound like they're for some guy with his eyes the size of grapefruits and his mouth large enough to swallow a watermelon whole, it completely pulls me out of the experience.
TL;DR: Final Fantasy English voice acting isn't actually bad (especially when compared to the Japanese) and it would be great if people could stop hating on it because that's the cool thing to do. SquareEnix needs to provide language options so everyone can be happy. SquareEnix also needs to improve upon their PC ports of future games.