Maybe discarded was the wrong word to use now that I think about it. I use the term "make sense" because, whether or not you don't see preparation as memorization or not, I do and both do the same thing. In the morning you prepare, or meomorize, a spell formula, you cast it, you forget it. Gone. To me, logically, that just does not make sense. Frankly, if you know the spell, you know it, and if you don't, you don't.
You read books, and only official Dragonlance books and FR books simulate magic that way, and even reading those books, when a spell is cast most of the time the caster feels the magic pulsing through their bodies, sometimes getting tired over the course of the day the more they cast spells. In other words, in their own books, the spellcaster feels the effects of manipulating magical energy, casting spells, however you term the usage, and they get tired. If they cast a more powerful spell, they get more tired and feel drained. Dragonlance is big on this, especially in the Chronicle's books.
Other non-DnD books of fantasy using magic simulate magic as something people tap into, using the energy to form spells that tax the body. The more powerful the spell, the harder the spell is on the body because the power of the spell is taxing to the caster.
The DnD system is okay and designed the way it for balance issues, and I understand that. But it could be so much better. I also agree that most people, if its not official in the core rules, will not play with it because it doesn't come from the official company itself. That is the falacy of DnD itself.