when they cast a spell, they forget it

This always bugged me, and I don't like how wizards need to have a wing of a bat in their bag just in case (seems more like witchcraft IMO).

One of my favourite parts of third party RPGs and homebrew is that all magic has a chaotic component, so a fail can cause some weird effects from blowing your hand off to giving everyone in a radius boils ;)

Personally, I think magic would be more like a power reserve than "I prepared these specific spells".

Wonder how Doctor Strange magic fits, I do have the marvel RPG from back in the day I will need to look it up.

I love magic systems, one of the best brains to talk about them is Brandon Sanderson

https://www.brandonsanderson.com/sandersons-first-law/