Been on a big Lord of the Rings kick lately so here are some very open-ended thoughts on an OSR clone inspired by the sensibilities of the LOTR books and films and related items (like Three hearts and three lions).
It's not intended to be explicitly Middle Earth and is probably broken, its just a quick draft.
The core engine would be something very similar to the Labyrinth Lord "Advanced edition" which is basically BX stats with AD&D classes.
Everything assumes that campaigns tend to end around level 8-9.
Elves, Dwarves and Halflings stay.
Half-orcs are orcs that have turned against their masters and can potentially pass for human at a distance.
Level limits are gone (due to the low level cap anyways).
For now, the GM handles all questions of who can play what race.
Humans get a +1 bonus to all saving throws.
I'd throw out Gnomes and replace Half-elves with something closer to the MERP Dunedain/Rolemaster "High Man".
Gain the OD&D "sweep" ability against 1 HD enemies (1 attack per level).
Match AD&D 1st edition but add Orcs to the favoured enemy list.
Spell-casting ability kicks in 2 levels earlier and represents ranger "tricks" and "talents" rather than actual magic.
No memorization but uses per day are still limited.
NO healing and NO direct damage spells.
Stay but lose all spell-casting.
Focus on being a Knight type of character.
NO direct damage spells. Sorry guys.
Mages have a Willpower pool equal to the average of Wisdom and Charisma.
Casting a spell uses 1 willpower point per spell level.
Once used up, the Mage becomes subject to a negative personality trait chosen by the player at creation and any further magic use will drain hit points.
XP requirements reduced to those of a fighter.
Becomes Priests. Gain Hit Points similar to a Thief in your parent rules system (so D6 if using AD&D).
Spells require half an hour of ritual per spell level to cast.
Remain mostly as is.
Becomes Scouts. Gain same Hit Dice as Clerics.
Dungeon-related abilities work in wilderness instead.
Pick pockets gone. Lock picking becomes Path finding.
Gain +1 missile shot per round at all levels where backstab damage increases.
Backstab attack bonus (but not damage) applies to missile fire from concealment.
Use 2nd edition AD&D bard or, ideally, the 1st edition illusion-oriented variant from Dragon Magazine.
NO direct damage spells.
Maybe delay magic use by 1 or 2 experience levels.
"Spells" are actually the effect of lore/tales and charm, not magical as such.
Monks and Assassins:
GENERAL GAME EFFECTS
A nights rest restores 1 HP per experience level. A harrowed night without rest restores 1 HP.
If struck by poison, put 3 Poison markers on character sheet.
Each poison blow while already poisoned adds +1 marker.
When its your round, roll a save for each marker.
Each succcess removes a marker, each failure costs 1 hit point.
Monsters of level 6+ inflict 4 markers.
Level drain attacks do the following:
Inflict +1 damage per level of drain in the normal rules.
Inflict 1 point of Burden per level of drain in the normal rules.
Characters accumulate Burden when in the presence of evil magic, struck by level-draining creatures or when a decision incurs a loss on a friend or ally.
One point of Burden is shed after each gaming session. A great success in the story may also shed a point.
A player failing a saving throw or attack may ask for a Lure.
IF the GM offers it, the saving throw succeeds (and any resulting damage or effect durations are halved). An attack will succeed at maximum damage.
Track the number of Lures.
At any later time, the GM may spend a point of Lure to force a character to roll two dice for a saving throw, taking the worse roll, or roll two attacks for a monster applying damage for both.
Alternatively, the GM may spend a point of Lure to add a complication to a successful roll.
"Yes, you climb the wall, but a piece of equipment falls from your belt, alerting the guards that something is afoot".
When reduced to zero hit points, your character is Dying.
Add 1 Burden immediately.
At the end of each round until treated with first aid, roll a D6 for every point of Burden with a 6 causing an additional point of Burden to be added.
Once treated, your character must make the above roll once per day.
If Burden reaches 10, your character has perished. There is no resurrection and no raise dead.
Once receiving proper care in a friendly environment, with a dedicated caretaker, remove one Burden per week. After one week ,you are able to adventure again.