No one is criticising Gygax’s design skills, but the concept of “balance” simply did not exist in the 70s and early 80s
I don't think this is quite right. Gygax refers to
balance multiple times in in his DMG:
Preface
Limitations, checks, balances, and all the rest are placed into the system in order to assure that what is based thereon will be a superior campaign . . . (p 7)
Alignment
It is of utmost importance to keep rigid control of alignment behavior with respect to such characters as serve deities who will accept only certain alignments, those who are paladins, those with evil familiars, and so on. Part of the role they have accepted requires a set behavior mode, and its benefits are balanced by this. (p 24)
Matrix for Clerics Affecting Undead
. . . If for some reason you must have an exact progression, follow the columns for levels 1, 2, and 3, correcting to the right from there - and thus rather severely penalizing the clerics of upper levels, but by no means harming play balance. Column 4 will then read, top to bottom: T, 4,7, 10, 13, 16, 19, 20. Do not otherwise alter the table as it could prove to be a serious factor in balance - weakening or strengthening clerics too greatly. (p 76)
Saving Throw Modifiers:
DM Stipulations: You may assign modifiers to any saving throws as you see fit, always keeping in mind game balance. (p 81)
Experience
Tricking or outwitting monsters or overcoming tricks and/or traps placed to guard treasure must be determined subjectively, with level of experience balanced against the degree of difficulty you assign to the gaining of the treasure. (p 84)
Economics
You may, of course, adjust any prices and costs as you see fit for your own milieu. Be careful to observe the effects of such changes on both play balance and player involvement. If any adverse effects are noted, it is better to return to the tried and true. It is fantastic and of heroic proportions so as to match its game vehicle. (p 90)
Monster Populations and Placement
Alter creatures freely, remembering balance. (p 91)
Placement of Monetary Treasure
In the event that generosity should overcome you, and you find that in a moment of weakness you actually allowed too much treasure to fall into the players' hands, there are steps which must be taken to rectify matters. The player characters themselves could become attractive to others seeking such gains. The local rulers will desire a share, prices will rise for services in demand from these now wealthy personages, etc. All this is not to actually penalize success. It is a logical abstraction of their actions, it stimulates them to adventure anew, and it also maintains the campaign in balance. These rules will see to it that experience levels are not gained too quickly as long as you do your part as DM! (p 92)
Placement of Magic Items
As the campaign grows and deeper dungeons are developed, you exercise the same care in placement of selected and balanced magic items. Of course, at lower levels of the dungeon you have more powerful single items or groupings of disparate items, but they are commensurate with the challenge and ability of participants. (p 93)
Non-standard Magic Items
The items must be such as to not unbalance the game. . . .
Never take a player’s word for any item. Do not allow its use in your campaign unless you know his or her DM and get a full explanation . . . This solves the problem of having a possible imbalance
brought into your carefully designed campaign.(p 118)
Magic Treasure
. . . most treasures will have magic potions, scrolls, armor and weapons. This is carefully planned so as to prevent imbalance in the game. Keep potent magic items rare. (Increase scarcity by destroying or stealing what is found!) (p 120)
Magic Items
. . . the MAGIC ITEMS table is weighted towards results which balance the game. (p 121)
Notes Regarding Artifacts and Relics
. . . any creation by you must be done so as to maintain the item in balance with the game as a whole . . . (p 156)
Underwater Random Monster Encounters
Number of creatures encountered should be appropriate to the strength of the encountering party. (p 179)
These passages show that
balance is seen by Gygax to be relevant in a variety of ways:
*PC class abilities and restrictions;
*Monster design and numbers;
*The award of XP;
*Placement of treasure, which relates both to XP (if its money) and to PC abilities (if its magic).
I think these all cohere together pretty clearly.