Don't worry so much. That's not all of its secret characters. There's a third unique class special character who is actually really powerful even though he can't jobchange, and the rest of the secret characters can jobchange freely.
Usually I like to think I'm impartial but the class I ended up playing the least was the Oracle.
Going with the Mime and Calculator circle jerk.
I'd say Mediator and Bard but man, I just did a playthrough this week and used them both a troutload to great effect. Useful when you pay attention and know how to exploit them.
Not fond of the Archer. Maybe when you charged with the Archer exclusively you'd get an effect like 'don't move' and 'stop' with their arrows.
Or -1 Move or -1 attack for a couple rounds.
That is a really good idea. I wish they would have taken that approach with the job class rather than the generic Charge abilities.
My least favorite job class was probably Ninja, as it felt like it was poorly balanced against the rest of the classes. My least favorite special job class was the Holy Swordsman class as it makes Meliadoul, who joins after Orlandu, underwhelming at best.
Ninja is the best class in any of these games in terms of usefulness.
In terms of originality, I liked the Blue Mage in the TA series. And even though they were slow as hell and broke the game, Calculator was one of the more interesting classes in any RPG.
I've played FFTA but never found the secret jobs.
Bishops are terrible for their task, which is magic support of both the offensive and defensive type. Really just no point, specially given that the red mage is pretty good job (double/twin cast simply amazing). The orator probably the one job I remember trying out that I just didn't like. I'm also not big on paladins.
I didn't have the patience to play FFTA... too childish for my taste.
In FFT, I used only the mage classes to add some challenges. I used monk the least for being too broken.
This is actually the approach i'm taking on my current playthrough. Early on, one of my Knights learned weapon, armor, power, speed and mind break. I then changed her job over to an archer around the time you run into Dorter trade city ( when you can actually start getting Bows! ).
The result is pretty awesome. I can use knight break abilities at long range. Power break is great to effectively take a monster out of battle. He'll still be there, but he'll be swinging at you for less than half the damage. The rate of success in hitting one of these breaks seems to be 42% - 55%, depending on you and the enemy's position. Sadly, concentrate doesn't improve the success, but i'll take ~50%.
The problem with power break is that it gets considerably weaker as the game progresses. In the beginning it represents a far larger fraction of a monsters damage than later in the game.