I was reading this question, and it occurred to me:
I don't know why the designers of 5e chose this magic system. There are a lot of spellcasting systems out there, and I want to know why they choose this one.
In 3.Xe you had spells levels, and a caster had a certain number of spells per spell level per day, plus your character seemed to only know a limited number of spells (because of being a sorcerer or having a limited spell-book). This system was a little complicated, but navigable.
In 4e, you had simply "at-will," "encounter," and "daily" spells. This system was wonderful for spells, because your rarely had any question as to if your spells were available or not. (Unless your DM was bad at saying when fights ended or began.) It made the spellcaster better at lower levels, despite the observation that "pretty much everyone feels like a spellcaster" in 4e.
Now, in 5e, it seems you have a certain number of casts per level per day, but spells of particular spell levels can be cast at their level or higher. Seems like a pretty simple system. I'm all for simplicity, especially when it makes magic more approachable and less… arcane.
Anyways, my question is: barring any surprises, and assuming the 5e basics and playtest are indicative of how magic will work in 5e, why is the 5e Magic System the way it is?
I'd also accept an answer to: why did the designers choose to make the magic system of 5e this way?