Umm...I asked for ideas that didn't break the game, but all your suggestions break the game in one way or another. You may not see it that way ofc, but - from an objective view - they do damage the way the game works right now, and as it was designed to be.
Oh, I see now. So that's why. You want to deny this emerging reality due to your feelings of perceived cheapening/loss of accomplishment.
Anyways, please try to be understanding as I go through this...
So, you are in the "I had to grind countless hours to level to 50, and don't want some newbie to be able to buy a drink and do the same in an instant" camp, right?News flash: we all did the slow way, and many of us don't have a problem with the Zero-to-Hero potion. And in other news: this change is the reality now in Korea and China, and is coming to the rest of FF14 along with Bloodstorm! It was an inevitability - sooner or later, and it's pretty good timing for SE to release it with the next expac. And I - along with many - do believe that this is a positive and necessary thing for the longevity of the game.
Also, please do take into account that many newbies will likely not want either potion: either for being too pricey, or b'cos they want to experience the game the way it was meant to be played. However, there will be some who will want to just get the leveling potion, so they can just focus on the MSQ story, and not have to deal with the insane amounts of side-quests - and other distractions - just to level their class. And then there will be the newbies that were referred by their friends (or bf/gf/partner/spouse/etc.) who will buy both potions, so that they can do the same things together in the new expac. Ultimately, these "jump potions" simply give players more choice and flexibility - without breaking the game we all enjoy.
Boosted characters, right out of the gate, are the norm now in a lot of present day MMOs, and they are usually sold in each games' respective cash shops. And, this will continue to be more the norm as we go into the future. This is the paradigm that trends are shifting towards: as you said - instant gratification. And this paradigm shift was introduced by social trends stemming from social media, mobile apps and games: stats show that social media and mobile apps have made the average person's attention span shorter than a goldfish's. So, to meet this present and emerging trend, game developers, and their games, have to adapt to capture their audience, or risk dying out.
Now, please allow me to be blunt...
This is the inexorable truth: you don't have to like it, but you do have to live with it.