People aren't going straight to 70 with this. At end game they are still going to have to have levelled through 10 levels of expansion to get there. All it does is skip pre expansion stuff.
Jumping features have a price because it keeps them from being exploited by Botters, Gold Sellers and the like. Without that disincentive you would see an explosion in both in Stormblood content. That said, it would make sense to include a free one in the expansion.
Trying to change it so you can enter later in the MSQ isn't simple either. One of the most appealing things about FF14's story is its sense of continuation and progression. You get to know people and experience their growth with them. You go through events and earn your fame. That's hard for a random new guy to step into particularly given the fame involved in being the WoL.
This isn't to say that Jumping features can't be bad. Its that they don't have to be that bad. It all depends on how SE deals handles it and the freshly jumped player experience.
