^If old classes are kept intact, I definetely suggest "Master" class for the Venus Adepts, which is my favorite.
What I keep in mind, is to make every character's agility as high as possible, which makes everything little too easy. Well, maybe not if the boss uses a Djinn Storm, but yeah.
The last time I played The Lost Age, my party was:
[spoiler=Mah Party]Main party:
Isaac - Master (Lv 40) - Djinnis: 4x Mars, 5x Jupiter
Felix - Master (Lv 40) - Djinnis: 4x Mars, 5x Jupiter
Sheba - Sage (Lv 37) - Djinnis: 3x Jupiter, 6x Mercury
Piers - Guru (Lv 40) - Djinnis: 2x Mercury, 7x Mars
Backup party:
Mia - Pure Mage (Lv 38) - Djinnis: 4x Venus, 5x Jupiter
Garet - Paladin (Lv 39) - Djinnis: 4x Venus, 5x Mercury
Ivan - Ninja (Lv 38) - Djinnis: 6x Venus, 3x Mars
Jenna - Paladin (Lv 38) - Djinnis: 4x Venus, 5x Mercury[/spoiler]
With those djinni sets, all characters are faster than any creature in the game, except [spoiler]Star Magician and his minions.[/spoiler] And yes, that was my party when I last killed the optional boss, [spoiler]Dullahan.[/spoiler]
I hope there will be new ways to customize the classes and such in this new game. I really liked coming up with new methods as I played around with the djinni combinations.