I've been thinking about the ways characters advance in various games.
You get the systems that work off a leveling system. Basically these are a linear (or exponential) progression of characteristics, where a hero follows a specific journey along their chosen path. In some cases these systems may allow dual (or multi) classed characters, but it's still a predestined path.
Then you get point buy systems, where anything is possible as long as you spend the points and meet the prerequisites.
One of the more interesting character development systems I've seen comes from the Solar System (or The Shadow of Yesterday), where characters get XP for following specific paths that are relevant to their characters, then spent those points in a way that makes sense to the unfolding narrative (or at least that's the way I've played it).
I've had an idea for something that combines elements of all these ideas into a single development system.
It goes a little something like this.
Characters progress along a linear path with branches. At first the branches are close together, but eventually the branches get further apart. The first few branching points have already been passed, this part of the character's youth has been resolved.
Let's look at the base progression line of the character. (where lower case "o" represents an XP, and an upper case "O" represents a path branch).
A character starts with six experience points on their base progression line.
The character's childhood is taken up by the first path branch, their basic schooling comes from the second path branch, and an apprenticeship or start to their adult career occurs with their third path branch.
Each time the character passes a path branch point, they may start spending their XP on the benefits that this path provides or they may continue spending XP on the base progression line to reach the next branch point.
Each branch follows a similar structure.
Each time an XP is allocated to the path, an "o" or "O" is filled in...and if an "O" is completed, then the character gets to pick a new verb, a new ability, or may increase one of their elemental values.
At first, benefits come quickly and bonuses quickly empower the character, but the character develops, it gets more expensive to get the later benefits from each path, and it also takes longer to gain new paths.
Still needs some work, but it's feeling interesting at this stage.