So I'm playing a high level Paladin for a few weeks who has a rather high Charisma. According to the Table: Ability Modifiers and Bonus Spells, he would get spell slots above fourth level. How absurd would it be to allow any spell slots that are essentially "lost" due to Paladin's unfortunate lack of clerical spellcasting ability to simply be able to prepare more spells of their already known levels? It would seem appropriate, since were this a Sorcerer or Bard, I'd have gotten those spells anyway; and I hardly see it as overpowered since I'm not increasing the Spells DC, nor preparing a spell of fifth or above.
For example: If my charisma grants a bonus 5th level slot, being able to put a 4th level spell or lower in it.