I was always of the impression that Sneak/Invis (and even Deodorize) existed in FFXI because monsters that were likely to aggro were tuned to be fought in groups once you left the starter zones. Sneak/Invis were pretty much necessary as a component of basic travel for any hostile indoor area or any time you didn't have access to a chocobo in an outdoor area for whatever reason (assuming, of course, that you weren't beyond the level where aggro was an issue for that particular area).
I'm not sure how things are now, but when I played FFXI, even if you had someone in the party who could sneak/invis via spell, the expectation was that you would use your own consumables to get the job done because it was just too much of a pain in the *** for the caster to keep everyone stealthed.
I don't mind the idea of Sneak/Invis in FFXIV. I would, however, be disappointed if they were as necessary in that game as they were/are in FFXI. It was just another barrier in FFXI. Even as an alchemist that could HQ silent oil/prism powder out the wazoo, keeping myself supplied was tedious. And as someone who sold more than my fair share on auction, there wasn't an ounce of altruism in my business practices. I was out to earn as much as I possibly could from the sale of my goods and could, quite frankly, have cared less if that meant pricing out of the reach of lower level players. I had too many of my own expenses to be charitable at the auction house. If sneak/invis are to be necessary items, my hope would be that they would be shifted out of the player economy to an NPC so that the prices will always be stable and they will always be as accessible as SE intends for them to be.
This is pretty much exactly what I wanted to say. Sneak/Invis aren't the problem, and they're not a universal solution. They were a solution to FFXI's specific game mechanics, which involved moving through areas filled with monsters that could kill you in 10 seconds as you tried to reach a safe camp.
Since one of the main complaints SE seems to be trying to redress with FFXIV is the difficulty of soloing, it seems very possible that the monsters we EXP off of in this game will be considerably weaker. Wandering through areas as dangerous as the everyday spots of FFXI might be a rare occurrence.
In a game like that, Sneak/Invis might be needed much less often, and as a result they might be removed from the game or made more restricted than they are now.
I for one would love to wave goodbye to the constant chore and expense that was Sneak/Invis in FFXI. But it's an issue that has to be addressed from the ground up, in the basic design of the game.