I am really happy that Final Fantasy XV will be released in Sept. 30, which has been the social event of the 2016 to a die-hard Final Fantasy fan like me! Before the game come out, I have some personally thoughts about how FFXV dev team can perfect the game.
You can go tell the person to go turn down their music or whatever, but at this point, that person is locked out of the house. So, they can't turn it down even if they wanted to. The die is already cast. This truck is a' rollin'. You can't make a dead bird sing. And other such entertaining and colorful metaphors to say that you can write and do whatever you want at this point, but it won't make a bit of difference until after the console release. I'd suggest that you write your feedback after release. That way it will be a fresh post when the developers will actually be looking for feedback, and they may be able to do something about it. Right now, it will just be ignored and be buried in the additional feedback that comes in from the consoles. I am trying to help you here!
Tabata mentioned the deck idea, and you are not treading new ground here. I'm also saying that Tabata (peace be upon him) and his team (glory be thy names) have evaluated that possibility. For whatever reason, they couldn't implement it. I'm trusting that decision was made in good-faith and is overall the better choice given their many restraints in the project. If the developers say we can't do x because y, I'm going to trust them that it is the right answer until proven otherwise. I don't understand (well, a lot of what you wrote; I think you are coming from a frame of experience that isn't natural to me without first establishing a common frame through dialog) your point about since you are not a developer you are not going to trust that it is pretty much up to x unless you are a developer also? As a developer, I have no idea what sort of limitations their project is running up against. I can make some educated guesses, but I'm going to trust what they say.
Lastly, there is a point in setting realistic expectations. You as a fan don't have to concern yourself with market research, hardware limitations, physics of the speed of light (which is really just the speed of causality, and it is actually a limiting factor in modern computing. Go figure!), etc., but it does help you not think things like, "why are they doing this to me."
They aren't doing this to you. They are trying to make something awesome within the reality of the medium in which they are making it and the limitations of our physical universe and societies. They can't give themselves infinite resources. They have to make choices, and if you understand that they have made their choices for rational reasons that are not a personal attack on you or the fans, you'll have a better experience, and I know you love FFXV! I know you'll have a great time with it. Don't lose faith! Give them feedback, but just be aware right now - there isn't much anyone can do about it. I'd hate for your voice to be lost in the archives here. I'm fairly certain there will be a PC release, and it will have a window for feedback. I'm sure it will be great, and it will likely be better than the consoles. However, we will have to wait and see. In the meantime, keep doing you. Well on that note, I am going to dart off to other parts of the internet. See You Space Cowboy!
I second the question. One, the team is bug fixing and optimizing at this point. They are not going to overhaul the combat system for any reason at this point. This would increase the development and testing time while decreasing profits (present money is worth more than future money due to inflation; it isn't a one-to-one comparison to say the same number of people will buy the game regardless, which makes assumptions in itself). I know you say PC market, but you have to think not every PC gamer has the best system. What are the percentages of the market that will actually be able to make use of the new features? Will enough of them buy the game to make it profitable (not pirate the game)? I don't know the answer, but market research has to be done to justify the decision to make a FFXV HD Remix 2.0. The market may not be there to justify spending money to upgrade the game for the master race to enjoy a better FFXV.
Secondly, "Of course, I can get a hell of a good look at a T-Bone steak by sticking my head up a bull's ass, but I'd rather take the butcher's word for it." Tabata and the development team didn't have an evil developers meeting where they said, "We should make the players hate life and our game by limiting quick-slot options to only 4 slots. Think of their tears and the money they will oay when we release an 8 slot patch as DLC. Muhahahaha!" They have their reasons for doing things, and I trust them to have thought about this stuff with FAR more information than any of us have. Unfortunately, the time for anything other than small UI changes, bug fixes, and minor enhancements is long over. Give them a break, and when PC is officially announced and they say they will be adding extra development, then I am sire they will love to hear your ideas about what changes to make. However, even then, they are closer to the details, and they will make a much better decision than the fanbase sitting on the outside looking in through a tiny blsckedout window will.
In summary, let the dev team focus and finish, and then, give them constructive feedback while understanding they have to balance things differently than you.