I feel the current system is just a little too complicated and I thought i'd give a shot at creating one. Sorry it's so long but wanted to give examples to it all hopefully makes sense.
Resonance pool = Level + Cha
All Magic Items have either a Passive ability, Active ability or both.
Passive magical abilities need to be invested during daily preparations. (cost 1 resonance)
Active Magical abilities use either a Command, Focus, or Operate Activation (Cost 1 resonance point)
I think this system has a couple benefits.
1. Eliminating charges is one less thing to have to keep track of.
2. All Items basically work the same way
3. Gives the choice of having lots of items invested or lots of uses of activation.
Example A. Fighter: invests in armor, several weapons, and save a few points for trinkets or weapon active abilities
Example b. Wizard: few invests but many points for active abilities or staves and wands.
List of Magic Items as examples:
Weapons: in most cases weapons will just have a set of Passive abilities that will cost 1 resonance to use. Some could have active abilities as well
+1 Flaming Sword
• Passive: +1 potency, flaming Property (cost 1 resonance when invested)
• Passive: +4 Potency, flaming Property, Shock property (cost 1 resonance when invested)
• Active: Whenever you critically hit with the sky hammer, you can activate it to cast a 6th-level fireball spell, centered on the sky hammer, as an innate arcane spell. You are immune to the fireball’s effect, but any allies in its area are not. (cost 1 resonance when use command activation)
Armor: in most cases armor will just have a set of Passive abilities that will cost 1 resonance to use. Some could have active abilities as well. Similar to weapons.
+1 Fortification armor
• Passive: +1 potency, fortification property (cost 1 resonance when invested)
Shields: in most cases shields will just have an Active abilities that will cost 1 resonance to use. Shields usually require the use of a raise the shield action to trigger its abilities. Similar to weapons and Armor.
• Active: you can activate it to animate the lion’s head and immediately make a melee Strike with the shield as part of the Raise a Shield action. (cost 1 resonance when use focus activation)
Other worn items: in most cases has a Passive ability and Active ability.
Cloak of Elvenkind (standard)
• Passive: Item bonus (+3) to Stealth checks (cost 1 resonance)
• Active: Cast invisibility for 1 minute (cost 1 resonance when use focus activation)
Scrolls: A scroll contains a single spell, which you can cast without having to expend a spell slot. Must Have the spell on your spell list. This is an active ability. (Cost 1 resonance point when used)
Scroll of Illusory Disguise
• Active: Cast Illusory disguise (1 level) (costs 1 resonance when use spell casting action)
Staves: Staves will have both a passive (cost 1 resonance to invest) and active (cost 1 resonance to activate) ability. There is no limit to how many times you can activate a staff’s active ability however each time costs 1 resonance point and the spell needs to be on your spell list
Staff of Healing (minor)
• Passive: Adds an items bonus (+1) to HP restore any time you cast a heal spell using your own spell slots, spending resonance to use the staff, or from channel energy. (Cost 1 resonance point when invested)
• Active: Stabilize (cantrip) (cost 1 resonance point when using cast a spell activation)
• Active: Heal (level 1) (cost 1 resonance point when using cast a spell activation)
Trinkets: Trinkets are one time use Active ability items that can be used when it’s trigger is met.
• Active: when you critically succeed at an attack roll with the affixed weapon (trigger) you can activate the claw to gain the weapon’s critical specialization effect. (spend 1 resonance when use focus activation)
Wands: Similar to Staves but with only an active ability. There is no limit to how many times a wand can be activated (no charges) however each time costs 1 resonance point and the spell must be on your spell list.
Wand of Heal (1st level)
• Active: cast heal at given level (cost 1 resonance point)
Potions/Oils Do not cost resonance to use.
Quick Investment: Spend 1 round focusing on an item and spend 1 resonance point to invest in the item.
• This is for say a fighter that has many weapons so be able to invest on the fly or in the case of a weapon being broken mid combat another character can give them a weapon to use.
• Maybe during that round you’re flatfooted. Since you’re focusing on the item.