What about Mystic Knight?

[Ultimatecalibur]

Yes because nothing is more exciting in a new expansion than being forced into last expansion's content in order to level from 60-70. Doesn't solve how they will be halted from progressing the Main Story because it'll be locked behind dungeons every few levels.

Not everyone is going to jump to the new jobs first and not everyone will try to level the new jobs 60 to 70 with the MSQ. A large amount of the queue jam with the new jobs at launch is going to be in 50 to 60 content just like how much of the queue jam in HW was in 30 to 50 content. Roleless content, the possibility of running dungeons with squadrons and changes to how chocobos function should spread out the player base much better than HW's "only way to level is with dungeons or FATEs" system.

Exactly. I think when a new expansion comes out... people don't want to go back to old content for a while, this would make a terrible launch on a shinny new expansion filled with new content.

RDM and any other new jobs are starting at level 50 not the current cap of 60 (unlike Blizzard which put their new classes directly into new content). Anyone leveling the new jobs will be leveling with "old" content first.