The Battlemind, Warden, Ardent, Avenger, Swordmage, and Invoker all seem to exist for little reason beyond the grid-filling WotC says they don't do. Yet every box in the grid is filled /except/ the Martial Controller. No controlling without magic, here, have a little dose of Primal, now the spirits will let you be a Controller.
The Battlemind and Ardent were tossbacks to 3.5s psychic warrior and ardent classes; both of which even in 3.5 was a psionic fighter and and a psionic cleric. (FYI: there was a psionic rogue too; the lurk)
The Avenger and Invoker felt a bit forced. While the idea of a divine assassin could support its own archetype; it probably could be a paladin build. While the invoker probably was a stronger archetype when there was a spontaneous caster (favored soul) and a prep caster (cleric) but in 4e's system, the classes could be done as a different cleric builds.
The Warden should REALLY have been a barbarian build.
The Swordmage though seemed a good mix of arcane and martial without resorting to multi-classing (and a nice nod to the elven F/m in basic).
I could also see the runepriest and the seeker as alternate builds of the cleric and ranger.
I could also see Warlock and Sorcerer rolled into one, but that's getting technical. A dragon-pact, cosmic-pact, chaos-pact, or storm-pact warlocks probably would have worked easily, but I don't mind them divided up into two classes.
Thematically; I see no problem with druid, bard, ranger, paladin, warlock, barbarian, shaman, warlord, artificer, and monk, either as separate classes and unique archetypes.