That's a great idea, partially because it's so much simpler and easier to accomplish than anything else I thought up. Thank you.
I'll put the world file up for download once I work a few things out.
Currently, here's what I have working.
Hau - resistance
Kakama - speed
Kaukau - water breathing
Pakari - strength
Miru - jump boost
Huna - invisibility
Ruru - night vision
Avohkii - night vision
Akaku - night vision
Vahi - slowness/min.fat. potions
Iden - resistance/invisibility/weakness potion (you can’t be seen, can’t be hurt, and can’t hit others until it wears off)
Calix - overall physical buff (slight boost in speed, jump, strength…)
Volitak - invisibility
Tryna - skeleton spawn eggs? (To be added)
Zatth - guardian spawn eggs? (To be added)
Olmak - ender pearls
Crast - knockback V item
Avsa - wither/hunger potions
Jutlin - poison/weakness potions
Kualsi - ender pearls
Kiril - regen
Armor Types *
Nuva Armor - boosts damage and protection
Toa Elite Armor - boosts HP and protection
Fire-Forged Armor - boosts HP and fire resistance, reduces speed slightly
Wind-Speed Armor - boosts speed and jump height, reduces health slightly
Subaquatic Armor - boosts speed, depth strider, respiration, proj.prot., reduces health slightly (definitely the weirdest combination)
Basic "creation" - placing blocks which are instantly changed into leaves (plantlife), fire (obviously), coal block (earth), water (water... duh), etc.
"Invisibat" techniques - summoning an invisible bat, armor stand, or other entity to the position of an enemy, then summoning lightning, spreading fire, etc. around them
*The special armor types might be removed; it would probably be easier for me to associate elemental powers and items with armor for players, and it would also allow some neat bonuses (i.e. depth strider for water Toa)... but the special armor types are still in for now.