@Water Akira: Remember, the Adept class is mostly offense oriented, so healing and defensive spells, while possible, would be rarer and weaker. Out of the two options you listed, though, I like the Metal Adept the best--light mages are so often seen, but not many to my knowledge (besides Gajeel Redfox, Servant Archer of Fate/Stay Night, and one more that I can't actually think of right now but know I've seen) use metal element magic. That's just me though, you should go with whatever you like the most.

@BlueAngel: If your priority is debuffing and status effects, a Cleric actually would be your best bet. They heal and buff allies, but debuff and cast things like Sleep on enemies.