When I work with settings that contain magic, whether traditional fantasy or others, I always perceive something of a tension when trying to portray the magic between the following factors:
- Magic that feels magical/mystical rather than just another strand of science/technology
- Coherency and internal consistency
- Availability to PCs
Are there any systems/settings out there that balance these particular factors, and is there any advice you can give on putting together a system of magic that balances the three factors for a setting?
Edit: Just some extra notes on #2. based on some of the answers and comments: I'm not averse to uncertainty or random elements (chance of failure, unexpected results etc) but I'm keen to avoid elements creeping in that have the players cease to believe that there is any reliable, common thread to magic. It's about thematic believability and internal consistency rather than predictabilty.