Thanks.
Obviously all elucubrations on core spellcasters' "brokenness" are strongly conditional on the spellcasters having the spell slots to cast the desired spells, and actually being able to cast them. Easier said than done, however, because in my games, following the DMG guidelines/variants:
1- I ruthlessly enforce random encounters, per DMG guidelines, both in and out of the dungeons (the wilderness is a Very Dangerous Place, see DMG p.133). The players never know when they may need a Neutralise Poison, because you know, there are many poisonous critters around; perhaps giving priority to Divine Power isn't such a smart idea, after all...In general, random encounters ensure that the players DON'T determine the pacing of encounters and the option to rest. I can count on one hand (in 23 years) the times the players have had the luxury of going "nova", and that's just out of sheer luck. Also, it's fundamental to follow the encounters distribution table: (DMG p.102) 50% of the encounters will be at the party's EL, 30% at a lower EL, 15% up to EL+4 higher, and 5% EL5+; the players must know when to retreat, because...
2- All of the encounters are Status Quo. "Here there be dragons" is a warning!
3- I exclusively use the "organic character creation" option in the DMG, which ensures that PCs don't necessarily have the highest scores in the abilities they desire most (e.g. Constitution for Concentration, or Dexterity for AC, or Strength for melee.) I have had wimpy clerics and buff wizards at my table.
4- Intelligent adversaries will always target spellcasters as a matter of priority, and they will work in concert by flanking (so that 5' steps are useless) or, even better, surrounding; so that they can Ready actions to interrupt the spellcaster (whom are not guaranteed to have high enough Constitutions, by the assumed organic character creation). Enemy spellcasters will try to counterspell, obviously. So, the "useless" Fighters and Rogues are in a uniquely good position to actually intercept and engage adversaries to give spellcasters the necessary freedom to cast spells. The act of casting a spell must NEVER be taken for granted; the players should never consider that casting a spell is a simple option, and should think that using magic items is a better option for this reason, however...
5- Creating magic items should not be easy; the "power components" variant in the DMG guarantees that it's not a rote process, and that it's also VERY costly (I use the maximum x20 multiplier suggested in the DMG). Hacking the Wealth by Level table (by at least halving the values, per "low magic" considerations in the DMG) however reduces both the looted money and looted magic items (at 1/2 the value, you get "delays" in loot gains by at least 1, to about 3 levels). So, money will tend to be scarce (and needed for training, and for healing, and for resurrecting...), and the number of magic items found will be small. In short, recreate the "AD&D environment," which wasn't kind on spellcasters.
6- Make sure that ALL spells are appealing, not just the combat ones. Spellcasters should constantly face cost-opportunity choices, like memorising Neutralise Poison or Divine Power? Is Comprehend Languages going to be useful? Arcane Lock may be necessary to get some time to rest! What about Tenser's Floating Disk?
7- All sorcerers must have patrons (DMG variant p.42) so that gaining new spells is not automatic, and subject to bargains with entities which have their own agendas, and not all patrons are what they seem...Similarly, wizards must do spell research (DMG p.41), which has a time AND monetary cost; but money is not really plenty (due to WBL reduction). And finding scrolls and spellbooks is also not easy (again, WBL reduction.) Bards don't have it easy, either; scouring the countryside for new songs, rumours, etc. costs time AND money (DMG p.42)
All of the above is pretty much "by the book".
