Baldur

A skill that nullifies detect. Once a player has Detect, any kind of grandmaster Sneak & Hide automatically becomes voided. 

Status Effect Buff/Debuff Mods: Ones that can actually hinder a raid boss. I think I mentioned this in the 3.0 Thread. But we can always use more Support Mods. 

Exhausting Hate: No post action removes x Hate from you.  

Perfect Shadow: Re-stealthing in Combat. You gave us surprise attack; awesome. Its a one hit wonder but nothing more. Giving us the ability to restealth during combat will make this so much better. Perhaps negating the +1 Dmg after the first Surprise Attack is used.  (Still requires a post action to go into stealth mode) 

Iffy Support Mod: Relive: Brings back a character that 'died' during a battle. They are resurrected with 5% of their HP and will be 'stunned' for a turn. (1 per thread) 

Some ideas. 

+1 for Arcs ideas. Having GMed our weapons and giving Specific Weapon based Mods would be pretty neat. 

@Opal

I'd suggest the following alternative to the revival mod concept, since there was only one resurrection item in canon and it was extremely rare:

Prayer of Protection: 10 turn cooldown, turns counted on your post- Designate target player, and that player gains MIT equal to their max HP until their next turn.

This offers the player a fighting chance to survive in a hopeless situation without breaking the bank of the role of death in SAO, I think.

Feel free to refute this, of course.