O.k. so here's the system I've been thinking about.
First you have generic skills. Each class has at least one generic skill. They cover multiple areas, meaning that it's not too hard to find uses for them. They are:
[Nature] Ranger and Druid only. Includes herbalism, tracking, animal handling, wilderness survival, geography, geology, monster identification.
[Healing] Cleric and Druid only. Includes medicine, curing, potions, diseases, poisons, antidotes.
[Arcana] Wizard and Sorcerer only. Includes detect magic, spells, runes, symbols, rituals, secret codes, ancient books, ancient languages.
[Religion] Cleric and Monk only. Includes detect evil, detect undead, gods, demons, churches, sects, temples, monasteries, history, the planes.
[Warrior] Fighter and Barbarian only. Includes athletics, climbing, swimming, jumping, riding, jousting, break open doors and chests, appraise weapon and armour, legendary weapons and armour, metals, intimidation, leadership, marshalling.
[Assassin] Death Knight and Rogue only. Includes critical strikes, anatomy, vital spots, autopsy, inflict pain.
[Psionics] Psionicist and Psychic Warrior only. Includes telekinetics, telepathy, lie detection, mental suggestion, mind manipulation.
[Streetwise] Rogue and Bard only. Includes bluff, sense motive, gather information, appraise, bargaining, underground factions, criminal organisations.
[Word of Honour] Paladin only. Includes honour, oaths, rules, nobility, royal families, elicit trust, diplomacy.
Then you have additional skills which are more limited in their application and are restricted to one class or one race. Here is a non-exhaustive list:
[Monk Diamond Body] includes poison detection and poison neutralisation.
[Druid Clairvoyance] includes conversing with animals, conversing with stones.
[Bard Charm] includes charming an NPC of the opposite gender, elicit courage.
[Bard Perform] includes singing, playing instruments and telling stories. Requires a musical instrument in the inventory.
[Bard Knowledge] includes knowledge of legends, heroes, famous warriors, artefacts.
[Rogue Search] includes searching for secret doors and secret buttons.
[Rogue Open Lock] includes lock picking and disarming. Requires thieves' tools in the inventory.
[Rogue Stealth] includes stealthy movement and hiding.
[Rogue Pick Pocket] includes stealing, sleight of hand, spot sleight of hand.
[Rogue Deception] includes forgery and disguise.
[Half Giant] includes picking up, pushing and moving extremely heavy items.
[Small Size] includes gaining access to tunnels that are too narrow for bigger races.
[Dwarf Sense] includes detect sliding stone walls, detect gold, appraise gems.
How does that sound?
First you have generic skills. Each class has at least one generic skill. They cover multiple areas, meaning that it's not too hard to find uses for them. They are:
[Nature] Ranger and Druid only. Includes herbalism, tracking, animal handling, wilderness survival, geography, geology, monster identification.
[Healing] Cleric and Druid only. Includes medicine, curing, potions, diseases, poisons, antidotes.
[Arcana] Wizard and Sorcerer only. Includes detect magic, spells, runes, symbols, rituals, secret codes, ancient books, ancient languages.
[Religion] Cleric and Monk only. Includes detect evil, detect undead, gods, demons, churches, sects, temples, monasteries, history, the planes.
[Warrior] Fighter and Barbarian only. Includes athletics, climbing, swimming, jumping, riding, jousting, break open doors and chests, appraise weapon and armour, legendary weapons and armour, metals, intimidation, leadership, marshalling.
[Assassin] Death Knight and Rogue only. Includes critical strikes, anatomy, vital spots, autopsy, inflict pain.
[Psionics] Psionicist and Psychic Warrior only. Includes telekinetics, telepathy, lie detection, mental suggestion, mind manipulation.
[Streetwise] Rogue and Bard only. Includes bluff, sense motive, gather information, appraise, bargaining, underground factions, criminal organisations.
[Word of Honour] Paladin only. Includes honour, oaths, rules, nobility, royal families, elicit trust, diplomacy.
Then you have additional skills which are more limited in their application and are restricted to one class or one race. Here is a non-exhaustive list:
[Monk Diamond Body] includes poison detection and poison neutralisation.
[Druid Clairvoyance] includes conversing with animals, conversing with stones.
[Bard Charm] includes charming an NPC of the opposite gender, elicit courage.
[Bard Perform] includes singing, playing instruments and telling stories. Requires a musical instrument in the inventory.
[Bard Knowledge] includes knowledge of legends, heroes, famous warriors, artefacts.
[Rogue Search] includes searching for secret doors and secret buttons.
[Rogue Open Lock] includes lock picking and disarming. Requires thieves' tools in the inventory.
[Rogue Stealth] includes stealthy movement and hiding.
[Rogue Pick Pocket] includes stealing, sleight of hand, spot sleight of hand.
[Rogue Deception] includes forgery and disguise.
[Half Giant] includes picking up, pushing and moving extremely heavy items.
[Small Size] includes gaining access to tunnels that are too narrow for bigger races.
[Dwarf Sense] includes detect sliding stone walls, detect gold, appraise gems.
How does that sound?