I and many others I assume would love to see armor effects return in all their glory(meaning they will either take a lot of playtime/hard work to unlock)Here are some of my own. Please feel free to create your own.
Pink mist- A cloud of pink mist will follow the player around
Angel- A halo ring will appear above the players head, when the player dies they evaporate into light
Phantom- A purple cloud of smoke follows the player
Radioactive- Player bleeds yellow blood
Rainbow-A short rainbow trail will follow the players feet, thrust trail is rainbow
Demon- Small read horns appear on the players head,when a player dies their body will catch fire and burn away
Polygon- When a player dies, they burst into polygons
Falcon punch- When a player melees, their hand will catch fire.
Life-Green flames appear on the players head
Corruption- Black flames appear on the players head
Blessed- White flames appear on the players head
Haunted- Any visor becomes a skull
Ghost-The players hands and feet are always in bad active camo (not the weapon)
Phoenix- When levitating with thruster pack, fiery wings will appear behind your back. All deaths will have the disintegration effect.
Fishbowl- visor becomes a fishbowl, leaks when killed by a headshot.
werewolf- the longer your spree is, the more you become a beast (claws,small amounts of fur)
Cursed- translucent chains hang off the player.
Void- visor is removed and replaced by a black hole
Ninja- Energy sword becomes a katana, armor becomes pitch black