I am in the "for it" camp.
A lot of older games provide a way of boosting new players to current content. It's nothing new. I think the Story Pack idea is great because it fills the player in on the lore while catching them up.
I have a lot of sympathy for people who are busy all day, don't have much time to play and "fall behind" on content. It's not a great feeling when you think you are holding everyone back when they play with you. And when you're the one ahead, it's not a great feeling knowing they feel that way.
Personally, I haven't seen or thought of a compelling argument against Story Packs and the alternative suggestions I've seen all have their own issues. I guess one question to ask is - Since FFXIV seems to be the inspiration for this, does it seem to have any of the problems that people are saying it will cause? I don't think it does.
But in the end I trust DE to do whatever they feel is best for the long-term health of the game and I won't be fussed either way.