Very well put =D

These are my 2 cents:

The devs could let the existing classes have more skills and be able to equip more than one type of weapon. There would be 3 types of skills: 1) those that are usable by the class regardless of the weapon; 2) those that are usable with one weapon; and 3) those that are usable with the other weapon. This way, for example, GLD could equip one handed swords and 2 handed swords -> with the 1H, he would equip a shield and tank, becoming later on a PLD; with the 2H, he would do the DD role and become later on a DRK. Both jobs would share a small set of skills, but they would be really different in stats and main skills (changing the weapon could give the ability to redistribute stats).

Another thing would be to create more job-only skills, especially for those that are so unique and should not share skills with another job through the class system. Example: BLUEMAGE.

This would be a way to introduce less basic classes and more jobs and still allow players to play with all the classes they love.

Another example: the Arcanist class could receive a little bit of changes to be more "versatile", so it would evolve into 2 different jobs (summoner, which is long ranged, and beastmaster, which is melee focused).

Jobs like Redmage and Bluemage could even come from the same basic class, as long as the skills are shared in an intelligent way.

THAT also reminds me of our current CNJ/THM problem... something I don't need to explain, right? =D