The main modifications I'd make would be to the classes, partly to eradicate the weapon and armour restrictions, and partly to give the different spell-casting classes a bit more flavour and differentiation.
- I'd allow Clerics to use any weapon, as befits crusaders, followers of gods of war and the like. Depending on the nature of the campaign, certain deities may place restrictions on certain weapons, or may strongly encourage the use of others.
- The flipside is that Clerics only gain magical 'pluses' with weapons which were specifically consecrated to their own deity when created.
- Thieves can already use any weapon in Labyrinth Lord, so no change there. I would however limit them to doing at most 1d8 damage. I just don't like the idea of Thieves carrying two-handed swords around!
- Thieves would only gain magical 'pluses' from daggers.
- I'd make the provision for Thieves to wear any kind of armour - at a price. Wearing studded leather would result in all thieving skills being reduced by one level, and scale or chain mail by six levels. Armour heavier than chain would prevent all use of thief skills. The option's there at least...
- Magic-users can use any weapon, but, in the same way as Thieves, they cannot do more than 1d8 damage, and do not gain magical pluses from any weapon except daggers.
- Again similarly to Thieves, Magic-users would be allowed to wear armour at the expense of their spellcasting abilities. Wearing leather armour would reduce a Magic-user's spellcasting ability by one level, studded leather by two, and scale or chain mail by five. Armour heavier than chain mail completely prevents spellcasting.
- I'd probably allow Magic-users to cast minor 'cantrip' type spells freely, just to give low-level MUs a slight boost and to make them feel more magical.
Dwarf & Halfling
- The only change I'd make to Dwarves and Halflings is that I'd allow them to keep earning XP and increasing in level beyond their normal limit (XP charts to be decided). BUT the only thing they'd gain from each level increase above the usual maximum would be hit points.
- Like the other demi-humans, I'd allow Elves to carry on gaining levels above 10, but only their hit points would increase.
- I've never been that keen on the idea of Elves as wizards (or Fighter / Magic-users in AD&D terminology). I just somehow can't imagine them carrying big tomes around and studying ancient scrolls - that seems very much the preserve of the Magic-user class. I'm more into the idea of Elves as naturally magical, so to that end I'd make a few modifications to the way they use magic. Firstly I'd make the spell progression chart double up as not only spells castable per day, but also as an Elf's known spells. So a first level Elf knows one 1st level spell, which he or she can use once a day. The whole idea of spellbooks and finding new spells is done away with for Elves. When they gain a level, they just learn a new spell. Likewise, they don't need to do anything to memorize spells, the ability to cast spells simply returns after a good night's sleep.
- To further differentiate Elves from Magic-users, I'd even give them a completely different spell list - the Druid spell list from the LL Advanced Edition Companion. This would really cement their role as being innately magical, and tied to the forces of nature. Spells like Faerie fire, Obscuring mist, Plant growth, Passplant - those are totally what a self-respecting demi-fey would be using!
- Despite their change in spellcasting niche, Elves would still be able to use 'wizardly' magic items, with the exception of scrolls.
All the business with limiting which weapons the different classes can get magical bonuses from is partly a bit of 'niche protection' for the Fighter (only mighty heroes can wield the true power of legendary swords), and partly as a counter-balance to the eradication of class weapon limitations. I think it also makes a lot of sense as a parallel to certain other magic items like wands and rods being only usable by Clerics or Magic-users. It's worth noting that a magical weapon would still count as magical for the purposes of attacking foes which can only be hit by magical weapons, it just wouldn't provide any attack or damage bonuses when used by a character of the 'wrong' class.
As for shields, I think I'd say that Thieves and Magic-users can use them if they want to, but gain no AC bonus (including magical bonuses) from doing so.
One final rule I'd pull in (roughly from AD&D) would be a Strength-based adjustment to carrying capacity. Str 3 = -30lbs carrying capacity, and a maximum of 80lbs, Str 4 - 5 = - 20lbs capacity, max 120lbs, Str 6 - 8 = -10lbs, Str 13 - 15 = +10lbs, Str 16 - 17 = +20lbs, Str 18 = +40lbs. This would further discourage weak characters from wearing heavy armour and carrying large weapons, while still leaving the possibility there for a Thief or Magic-user who happened to have a decent Strength.