The 1-50 content is fine as it is you can level up your primary job basically just doing the MSQ, it is the level 50 and eventually the level 60 quests that can feel like a bit of wall for newer players but there are ways they can adjust this by removing all the fluff content in these patches so you just get the main story.

I think as long as the new jobs are available at level 30 for all players in 4.0 most people will be okay with having to do the MSQ to get to level 60, this level jump crap may get you some new players but if they are not willing to do the story in a story driven game, I don't see them playing much after 4.0 and in the process you risk pissing off your dedicated player base.

If SE ever implements this I will definitely be thinking of cancelling my subscription.