The current repertoire of classes and jobs is superfluous, at best. This can easily be seen by taking a look at the jobs needed to clear raids: Warrior, Black Mage, White Mage, and Bard.

So I suggest the addition of 4 Super Advanced Classes that any job can become by equipping a Super Advanced Job Stone. The 4 Super Advanced Classes are:

Super Tank
Super Mage
Super Healer &
Super Ranged Attacker

Super Tank
Super HP, Super Damage, & Super Defense

Super Mage
Super Spells from a super safe distance and Super AOE

Super Healer
Super Healing

Super Ranged Attacker
Super Ranged Attack from a super safe distance (with a few buttons to click that deliver Super Buffs)

WAR or PLD => ST
THM, CNJ, or BLM => SM
THM, CNJ, or WHM => SH
DoW => SRA

As you can see, it's a simple plan that will allow all classes and jobs to participate in difficult end-game content. It's a lot easier than fretting over how to include the original classes or the jobs that seem so useless to most even though they were just introduced in this very same patch.

Imagine what it would be like to see a shout like this in Ul'Dah:
(Looking for members.) Super Tank, Super Mages, Super Healers, and Super Ranged Attackers for (Instanced Raid.)