TL;DR:If a spell or action is granted to the player by having certain items equipped, that spell will utilize the spellcasting modifier of the class most recently taken by the player in its calculations, regardless of the relative strength of the modifier or the number of levels of the class versus other classes taken. I am suggesting that instead of defaulting to the spellcasting modifier of the class most recently taken by the player, spells or actions granted by having certain items equipped should instead use the highest spellcasting modifier of multi-classes taken.
In case you are unaware of this design feature, item actions (spells or actions granted to the player by having certain items equipped) will scale off of the spellcasting modifier of the most recently taken class by the player, and regardless of efficacy.
To better explain this, consider the following example:
I am a level 12 character with 10 levels of Storm Sorcerer and 2 levels of Tempest Cleric. I started the character as a Sorcerer, and then at level 11 took my first level of Cleric.
My Charisma ability score is 20 (for a CHA modifier of +5) while my Wisdom ability score is 14 (for a WIS modifier of +2).
If I were to cast a spell I learned from my Sorcerer levels, it will use the +5 modifier from CHA. If I were to cast a spell I learned from my Cleric levels, it will use the +2 modifier from WIS. This is working as intended and makes sense, as skills learned from certain classes should use the spellcasting modifier associated with that class.
However, if I were to equip an item like Helldusk Gloves which grant the use of the Rays of Fire cantrip, the action granted by that item will ONLY and ALWAYS use the +2 modifier from WIS.
This is because Cleric was the most recent class I added into my multi-class. It does not matter that I started the character as a Sorcerer and that I have the starting proficiencies of a Sorcerer or a higher CHA modifier than WIS modifier. The Rays of Fire scaling is locked into using the WIS modifier because Cleric was the class I added to my character most recently.
I am suggesting that the spellcasting modifier used in the calculations of spells/actions granted by items default to the highest spellcasting modifier of the multi-class instead of the current system which arbitrarily prioritizes the spellcasting modifier of the class most recently taken by the player. This feature is already available for the STR vs DEX ability modifiers on the item actions of finesse weapons, so I see no reason why a similar solution should not be implemented in regard to spellcasting modifier from multi-classed levels.
In the example above, this change would allow the Rays of Fire cantrip to utilize the +5 modifier from CHA instead of the +2 modifier from WIS, despite having added Cleric into the multi-class after taking levels of Sorcerer.
Please feel free to comment with any criticisms or concerns, or any constructive feedback on things I may be overlooking in this post.
Thanks!