So this might sound a bit silly, but given how we know that we're getting major tweaks and changes for various jobs, wouldn't it make more sense to allow players to get a feel for their current job before 4.0 so they would have a more comfortable footing going into the expansion rather than getting a good bit into the expansion to find out they hate how the job they've been playing before is now horrible to play?

The purpose of this would be to allow players to better understand what will happen to the jobs they normally play and give them a feeling for what job or jobs they would want to start off with so that they won't find themselves feeling as if they've been wasting their time leveling a job they used to like but has become less attractive due to the job changes. This is not something that was as necessary for Heavensward since there was not much change beyond new skills, but due to the emphasis of battle mechanic updates and job overhauls, I believe that earlier access for the players to at least the job adjustments on some level would provide a greater boon to players who want to make sure they can enjoy the game without feeling like they picked the wrong job partway through the starting storyline.

This isn't necessarily asking specifically for a 3.59 patch or any actual live implementation to bring the changes into the game early. This could also be something done through a benchmark program (like what was done for Heavensward) or an implementation of a simulator designed to test jobs (which could also double for a setup for job jump potions).

Yes, the new mechanics and job changes can be explained through live letters and other means, but even if each job is explained in every iota of detail--more so than they were for Heavensward--I still don't believe that this would be enough if the changes are as major as they have been claimed.

Again, the goal is to give players more adequate information on the job adjustments for players because those adjustments could make or break the current views of those jobs for players, which is not something I think players would like to learn midway through the leveling process.