Unlocking Content

[kyuven]

snip.

By removing dungeon entry restrictions and EVENTUALLY making it faster to progress to 50 (all games do this, and since they'll likely be adding more new jobs in 4.0 it'd behoove them to do it this way) they've already taken the steps to streamlining it.
You're still going to have to DO the MSQs up through 4.0 at the least, as they mentioned WAY back in the early days of 2.0 that that's how far ahead they have planned, but as it stands right now you're playing through the content.
Story driven MMOs strongly encourage you to, y'know, actually finish the story before moving on to the next.

If FFXI, Vindictus, Neverwinter, Star Trek Online, The Secret World, and SWTOR are any sort of example, you're not going to be able to SKIP the main story, but you will be able to move through it at a faster rate, i.e. be able to go from 1-50+ JUST on MSQs without having to pick up other quests on the way.
But the idea of just unlocking everything from the get go is absurd for this game's structure. Even games as ancient as EQ1 and FFXI have access restrictions on certain pieces of content even to this day. Hell to do almost anything worthwhile in XI, you NEED to be nation rank 6 at a minimum (that game's equivalent of killing Ultima Weapon in this game). It's simply their design philosophy, and personally as a general rule if it's a philosophy that crossed over from XI to XIV and made it through all the way to 3.0, I kinda doubt they'll be dropping it.

The next expansion could be like, you know, A realm rebirth or something. After blah blah blah before all the dragons are extinct, they lay a havoc upon the world blah blah blah, the world went into chaos.

Hence we start anew in 4.0 just like when 2.0 started from 1.0. All the previous story line will be lost along with the Illuminati Cheese.

Somehow I doubt they'd pull a "cataclysm" for the SECOND expansion, especially since they already did one.