I've been somewhat following the kind of hilarious drama going on with the Jobs right now, but I wanted to offer a solution if you all think it might be a good idea or not:

Delete the Roles as it is:

For instance let's take a Paladin Player -

He can setup his gear and skill tree to be more based in a healer, offensive or Defense role.

Each Job will have a unique set of skills that offer different benefits for the party.

Technically the Job Roles will still be there as you would still need at least two healers, but the difference is that every Job can do it and are no longer bound to their restricted job role.

Each Job will have their own strengths & weaknesses depending on the Gear/Skill Path the player has chosen for that job.

So the system as follows:

1) All Gear in the game are no longer bound to a specific Job Role with the reworked Job System, all Gear is now more based on the stats you want for your Job. Want your Paladin to be a hybrid Defense/Healer Skill Tree? Go for it. Want your Paladin to be a full healer skill tree, but lacking in everything else? Go for it. Want your Paladin to reign down its own set of Holy Magic on everyone (Magical Based Paladin) or go full packing steel with your holy sword (Physical Based Paladin)? GO FOR IT.

2) All Skills in the game are re-worked to follow the changes, and new skills added to make up for the deletion of the restricted Job Role.

3) Skill trees added for every job that follows a certain path that give abilities that are defensive, healer or offensive based and all come with unique ways to deal with a battle situation. However due to this change there is a limit to how many skills can be slotted to the hotbar to avoid balancing issues.
===================================================================

How would this Skill Tree look like?

So for the Paladin Class as a example again >
Healer Skill tree
Magical Based DPS Skill Tree
Physical Based DPS Skill Tree
Defensive Skill Tree

The Four main branches, all of which you can mix and match to fill your needs for the party as it calls for it. You can save multiple Skill Tree Paths so you quickly hotbar them without having to manually do it every time if your party wants your Paladin to go into a certain role.

This also allows for a lot of experimentation in combat to be tried out.
===================================================================

How this system could fail:

I understand people wanting to go to the path of least resistance which is inevitable because "Meta".

This is why Dungeons, Bosses, and Monsters need to be carefully designed so that Meta Builds cannot exploit their way into victory.