I just had a great idea hit me at work today.

What if status effects had levels like magic spells do? Each level would keep the same theme of the effect, but get progresively worse. It also allows for a much greater variety of (useful) status protection gear. You could have items that block all Lv1 status effects, items that downgrade all status effects one level, ect...

Here are some examples I came up with off of the top of my head:

1 - Disease - Lowers effectiveness of healing items
2 - Poison - Drains current HP
3 - Venom - Drains max HP

1 - Darkness - Lowers Accuracy
2 - Blind - 100% Miss Rate on Attacks
3 - Blackout - 100% Miss Rate on all techniques/magic

1 - Fury - Increased Miss Rate / Increased rate of limit break charge
2 - Berserk - Auto Melee Attack / Increased Power
3 - Kamikaze - Stores energy for one turn then self destructs.

1 - Sediment - Damage taken reduced 50% / speed reduced 50%
2 - Break - Turned to stone
3 - Petrification - Turned to stone, will shatter for entire battle after taking 3 hits

1 - Bane - All attacks against you do 2x damage
2 - Doom - Countdown timer to instant death
3 - Death - Instant Death

1 - Mute - Spell effectiveness 50%
2 - Silence - Can't use spells
3 - Curse - Can't use spells, drains MP

Some of the names could use some work, but I think I've managed to include most of the FF mainstays.