I forget where in the multitudinous blogoland, but someone posted a comment to the effect that high-level characters in Lamentations of the Flame Princess (think basic D&D with player character power dialed a bit down) don't do well in high-level AD&D modules made for more souped-up characters.That may be so - and is doubly true of my own 52 Pages rules where you can't come in with 4 magic missiles and 2 fireballs prepared at the same time.
I mean, great. The less overwhelming your high-level characters, the more you approach the ideal where big scary monsters are actually a threat to them rather than resorting to blind-tiger gimmicks ("you wake up naked and bereft in an anti-magic zone") or stupid dumb munchkin armies of 4 beholders and 20 frost giants, etc. The fewer bonuses pile up on them, the less you feel you need to compensate in an eternal treadmill of armor class and hit bonuses.
Now, another assumption of high-level AD&D, that grittier referees may balk at, is the ubiquity of magic items. A 7th level character in AD&D is likely to be tricked out in at least +2 everything, or a couple of wands and many lesser items if a spellcaster. One answer to this, of course, is the low-magic campaign where items are rare. The answer I prefer is "keep Fantasia weird" and filled with magic, but balance strong magic - most +2 and definitely all +3 and above - with the cosmic revenge of the universe on tools that so defiantly flout its laws - with the karmic debt paid for owning a sword that cleaves bronze like butter - with, quite simply, the human energy cost of a stick that shoots death. Something's got to pay somewhere.
(In effect - a shallower and broader implementation of the 1st edition AD&D "random drawback" approach to artifact-level magic.)
30 Random Drawbacks for Magic Weapons and Armor (d20, -5 at +2, +5 for each plus above +2)
"Armor" here includes shields.
0 or less: No drawback
1: -3 to a random saving throw.
2: -1 to all saving throws.
3: Accentuates your worst personality traits. -2 Charisma
4: Constant whispering sound makes it hard to concentrate. -2 Intelligence
5: Estranges you from God and nature. -2 Wisdom
6: Exhausting to wield. -1 Strength if an armor, -1 Constitution if a weapon.
7: Makes unexpected, clumsy, confining moves. -1 Dexterity.
8: Take 1 hp damage when you equip it.
9: Take 1 hp damage when you un-equip it.
10: If you die while wielding/wearing it, you rise immediately as an undead creature of hit dice appropriate to your level, and attack the party immediately.
11: Has minuses instead of pluses when fighting one creature type (reptiles, undead, humans, etc.)
12: Animals are unfriendly to you while carrying it.
13: +1 of its enchantment vanishes for the day when you hit (weapon) or are hit (armor) on a natural 13.
14: You need to eat five times as much on any day you use it in combat.
15: While wielding or wearing it, unintelligent enemies attack you by choice.
16: When you are aware of an enemy, you have +3 move to go towards them, and -3 to go away.
17: To enjoy its magical benefit, requires you to forswear your religion and follow an obscure, nearly-dead god, wearing its symbol and following its strange customs.
18: Can't heal HP while you're carrying/wearing it.
19: Glows visibly when enemies are near, within 60'... but only if you already know they're near.
20: Jealous ... drops from your grasp if you're carrying another weapon (weapon), falls off your body if you're carrying any other magic item (armor).
21: Each time you do (weapon) or take (armor) 8 or more HP of damage in one blow, you lose 1 HP.
22: Fogs your vision, you can only see 30' in dim light.
23: Makes an audible screaming sound when it hits (weapon) or when you are hit (armor).
24: Only has its magical powers each day if exposed to the rays of the dawn.
25: You must rest and not attack one round out of five while wielding or wearing the item.
26: You lose the ability to speak while wielding/wearing it.
27: Gives -1 to hit (if armor) or 1 worse armor class (if weapon).
28: You hit your nearby friends (weapon) or your nearby friends hit you (armor) on a natural to hit roll of 3.
29: Any NPC's who see it and are able to wield/wear it must save (Will/WIS/spell) or become covetous and scheme to take it from you.
30: Powerful wizard/demon/undead creature thinks the item is theirs and begins pursuing you d4 weeks after you acquire the item.