In my experience, the people whom the champion fighter was made for usually end up trying to play a wizard instead, with poor results for both themselves and the rest of the table.
Yeah. Magic needs to be "simple" too.
I am convinced the casters need to be default spell points. I prefer this style, but genuinely feel it is better for the game as whole.
Spell points are simple. There is a single pool of "energy" to spend. Nobody ever misunderstands this concept.
There is a simple list of "prepare spells" that the player can spend energy on. Done.
Points are especially necessary at the highest tiers, of Levels 13 thru 16 and 17 thru 20. These levels feel way too bloated with too many fiddly little slots. 100% unnecessary. A single pool of spell points instantly fixes the problem.
Then the highest tiers casters feel simple, like superheroes. They have a list of powers, and can use them whenever they want.
For the sake of balance, Warlock style Short Rest spell points is the way to do it. Pool of points = Level + 1. Spell cost = slot. A slot 3
Fireball spell costs 3 points to cast. Per casting, one cannot use more points than Level/2.
Suddenly, mages are simple. Players still need to understand spell descriptions, but they dont need to understand all of them, just the few that are in their character sheet.
For the Wizard spellbook and its potentially unlimited spells, this is for advanced players. Even then they are swapping one or two chosen spells into their prepared list.