In addition to the above points, my main reasons for liking the Vancian system are as follows:
1) No siloing of spells. You can prepare all combat spells, or no combat spells, or any permutation. Which means you can spend one day fireballing everything in sight, and another day divining all of your enemies, and another day setting up long-term wards, giving you maximum strategic flexibility. As mentioned before, it basically comes down to being a superior system strategically where AEDU is often superior tactically, and I much prefer a system with both good strategic and good tactical capability to one with mediocre strategic and excellent tactical capability.
2) No enforcement of non-combat-ness. This is similar to the above, but in speed rather than number.
Wall of stone,
silent image, and
teleport are in theory non-combat spells, and some people lament being able to cast them so quickly (mostly the people who think that you should require the preparation of some utility spells because combat spells are better, protip, they're not), but when it comes right down to it
every single spell is a combat spell if you're creative enough. If the designers say "This is a non-combat spell, so we should make it not castable in combat," what they're actually saying is either "It's too powerful to be able to cast in combat" or "We're not creative enough to think of combat uses for this." Most of the time when they say it's too powerful for combat they're wrong--seriously, guys, you didn't need to make the 4e Silent Image ritual take forever to cast and cost gold--and the latter case is self-explanatory.
Also: All the time, I see people who dislike Vancian casting but like the ritual system, saying that magic should be long and involved and so forth. Guess what? Vancian casting
is a ritual system! You spend a long time casting a ritual...and then at the end, instead of having it take effect immediately, you stick it in stasis in your mind to be released later. All of the heavy lifting gets done in advance, which is why there are no super-long casting times in combat or skill checks--they were all done in relative safety over a few hours.
Neonchameleon said:
1: The Wizard has too much magic. A fifth level wizard makes Gandalf look like an amateur. If you cut the wizard (and other primary casting classes) out of the game, the top tier class that remains in the PHB is the Bard. Cut all the primary casters out and the best caster is still right at the top of the power tree.
2: The recharge times are wrong. Resetting your spells should be something much more significant. It works in classic dungeoncrawling where you make far to many wandering monster checks to make an 8 hour rest healthy. And the penalty for recharging isn't a night's rest but schlepping back to town. But for a less focussed game this does not work. It means that for any situation that takes time to unfold the wizard can reprepare quite happily. Make it at least a full day and much more of the problem vanishes.
That isn't a Vancian problem, actually, it's a 3e problem. In AD&D, wizards had many fewer spells (no bonus spells for high attributes, no focused specialist, no widely-available charged items, etc.) and spells took 10-15 minutes per spell level to prepare, each, so it took a 20th level wizard about 2.5 days to prepare all of his spells and he only had about 2/3 the spells of a 20th-level counterpart. Bring back AD&D-style Vancian instead of 3e-style Vancian for 5e, problem solved.