If you play 1st or 2nd Edition AD&D chances are likely you are already happy with the spells and the spell progression. But WHAT IF you wanted to play a game that allows wizards and other spellcasters to be more "High Magic"?
Note - The concepts below can easily be applied to other editions too, as House Rules.
Wizards and other spellcasters are already pretty OP (overpowered).
So what is the benefit of making them even more high powered?
Well, it depends on how you do it.
If you give the PCs lots of magical items then eventually everyone in the party becomes OP. So by then it doesn't really matter.
But if you keep a firm lid on the availability of magical items (eg. they cannot be purchased and are very rare) then the only magic the party encounters is the magic of spellcasters and magical critters. But if you keep a tight lid on magical critters and spellcasters are rare, then you also can make that aspect of the game also rare.
So why do this? What is the benefit?
Flavour. It gives the world a very different feel if magic is both very rare, but also very powerful.
Imagine feeling like you are in a low magic game. You are fighting orcs, ogres, giants, and similar non-magical critters. Supernatural critters, undead and magical critters are all rare. Then you run into an ogre magi, but this ogre magi has magic that is more powerful and the DM plays the ogre magi as being very intelligent and battle savvy. The "Die Hard/Bruce Willis" version of an ogre magi.
Which makes the PCs the equivalent of Hans Gruber and his goons. And you are losing. And every time the ogre magi kills one of the PCs he shouts yippy kai yeah m***** f*****!
If the DM is like myself, they are running a deadly campaign. PCs will die. We will roleplay their funerals and the players will eventually take their revenge on the ogre magi.
Suddenly magic is so much mysterious and dangerous.
It sets a very different tone.
And to make it clear to the players that this increase in magical deadliness goes both ways - the monsters and foes are deadlier, but so are the spellcasting PCs you need a way to make the PC spellcasters more powerful.
Thus I present:
So what is the Fs for? Favourite Spells.
For each spell level category the wizard gets to choose 1 Favourite spell. That spell will be their favourite forever and it cannot be changed. It is essentially a bonus spell that they always memorize every day and they do not need a spellbook to memorize it. It is automatic. In the case of Specialist Wizards (illusionists, evokers, etc) their Favourite spell must be chosen from their specialist school. This essentially replaces and supersedes the bonus spells specialists usually receives.
You will therefore notice that level one wizards start play with one 2nd level spell, their favourite spell. However even though 2nd level spells are more powerful, this is tempered by the fact that their casting level is still only 1.
Likewise when the wizard reaches 3rd level they now could potentially choose Fireball as their favourite spell, but because their casting level is only 3 their fireballs only do 3d6.
So yes, wizards now gain access to higher level magic at lower levels, and yes they get more spells overall. This makes them more powerful, yes, but again everything is a balancing act. Enemy spellcasters are now more powerful too.
Magical monsters should have at least 1 of the following adjustments:
1. Raise their casting level by 4.
2. Magical poisons have a -4 on the saving throw. Or alternatively a creature that did not have magical poison, now has it and it is quite deadly.
3. The DM can sometimes give negatives on savings throws (-1 to -4) for magical effects from monsters because the particular critter is deadlier.
4. Magical critters may have access to higher level spells or abilities.
5. The DM might even invent new magical powers that make sense for the critter. Such as Air Elementals being able to cast Control Wind or other wind spells.
So yes, you make the spellcasters more OP, but you also make the monsters deadlier. Then, like all DMing, it is just a balancing act between deadly monsters and powerful heroes.
Some groups might only have the 1 OP spellcaster while other groups might be all or mostly spellcasters so how much the DM needs to balance will vary.
Now you might think "Why not just use bigger monsters?" Why not use the equivalent of a giant magi instead of an ogre magi? Yes, you could do that. But strategically this is about smart play vs DM laziness. An ogre magi should be played as being intelligent, and a DM wanting it to be even more awesome needs to take that up to the proverbial 11th degree of hardness. Adjusting the standard monsters to make them more unique is important to increasing the challenge.
Take for example the issue of magical weapons found in loot.
The skeletons guarding the treasure are using horrible rusty spears, but if they are in the actual treasure vault why not have them use the actual treasure. A skeleton wielding a +2 sword suddenly becomes a bigger threat. Especially if the skeleton is somehow smarter and hides above the doorway and has levels in Thief... Skeletons with Backstab and a +2 sword. There you go. A challenge that your players will not be expecting.
Another alternative to this...
Take the normal spell progression charts for all spellcasters and cut the number of spells in half, rounded up. Spellcasters suddenly becomes way more squishy because they have so few spells and have to choose between defensive spells and attack spells. The smart ones who are powerful enough will definitely want Teleport or Dimension Door for a quick exit.
A world where magic is both rare and magic users don't get that many spells... Sounds much more dire. And valuable. Suddenly people are murdering other people just to get a +1 dagger.
The point is that DMs have the power to make these house rules and subtly change the flavour of their world.
Storytelling
Story wise a DM could work this kind of rules change into their storytelling, and they could make this power upgrade only effect a particular type of magic. eg. Only arcane magic, as used by wizards and bards. The sudden shift in magical power could even be a "World Event" caused by some strange mystical event that causes all arcane magic users to become more powerful.
eg. All of the party, NPCs, everyone suddenly hears a thunderclap from the sky and a shockwave knocks them off their feet. By the time they get back to their feet the wizards can all feel it... their magical power has been increased. They don't know what happened, but suddenly their magical energies have increased... There could even be an atmospheric effect of the boost in magic, with Northern Lights appearing over much of the planet and lasting for X hours.
Afterwards the PCs have to figure out what caused this sudden shift in their magical abilities.
(Such a shift could also be used to explain what happens when PCs suddenly switch editions. Imagine you are playing 2nd Edition and suddenly a thunderclap happens, everyone falls down, and then it is now 3rd Edition. Tada! Not that I would do this, I would rather just start a new campaign. But in theory a group of players + DM could hypothetically do this if they want to keep the same characters and switch editions.)
