1) FFT Vanilla features abilities locked by chapter. Namely Ramza. His job may technically change between chapters, I can't remember. I do know he has more skills available to him, and he losses access to some from chapter 1 to 2. so if you did not learn them in chapter 1, you lose them forever.
Your Ramza is replaced with a different Ramza between Chapter 1 and 2, and again between Chapter 3 and 4. No abilities are removed from his skillset during this process, just more are added to the end. This is far from what you seem to think exists in the Vanilla version of the game.
2) you are releasing the game in installments or at least piecemeal. is it really impossible to not include advanced jobs or certain abilities? (Again, i understand you can't do this now)
Both your posts seem to misunderstand something. You're expecting easy access to something high end in Chapter 1. That's not what we intend to do just because "Vanilla did it". They're there if you want them or if you feel you need them but they have requirements that reflect the points in the game you are "intended" to get them by design - the late Chapter 2 - mid Chapter 3 area. If you want them sooner you can get them sooner, but the further ahead of the "curve" you want to be, the more levels you need to gain - making monster encounters more dangerous. You're free to play the game however you deem fit, but expecting to get the best things early on easily just because Vanilla let you is silly. And yes, each Chapter will include the previous Chapter because it is one full game, not four separate experiences. We're merely releasing it in parts so people can actually play it as reasonable portions of the game are complete instead of waiting around on a 2-3+ year development cycle for the full thing to be done.
were too lazy
There are going to be changes to a lot of things for Chapter 2 (including some things regarding the JP system) but for the purposes of Chapter 1 and the scaling within Chaper 1 itself the 10 JP per action system gives you timely access to the skills the Chapter is balanced around you having access to.