In my ambitious game design, which I'm saving for much, much later. Techniques can be learned any number of ways, it will be a flexible system, I'll go into detail.
"Skill trees" that most traditionally know, in this game will only exist as part of "Schools".
A character has a Knowledge grid, the higher their knowledge, the bigger this grid is, allowing them to learn more by "equipping" skills. Once equipped into the grid, it cannot be removed except for via items that cause amnesia, such as the humorous "Hammer of forgetfullness", in which the character will hit themselves in the head, and forget the selected skill.
Anyway, back to techniques, a player can just gather individual, unrelated techniques and put them in their grid. A good player will plan and make sure their techniques have good synergy with their playstyle, such as a Strong Sword Slash if you have a high stat, a Magic Attack if your magic side is high, or a Magic Imbued Sword Slash if you have both those stats equal. A player could choose to ignore such things and give sword slash to a magic user, which will prove to be inefficient.
Anyway, in this way, a player has the freedom to choose what techniques they learn, even to forego learning simple techniques in favor of waiting to get more advanced techniques to put into their grid. {Simpler techniques still have some advantages over more advanced techniques, and don't go obsolete due to the way the system is designed.}
Now back to "Skill trees", those who choose this path, will get a large portion of their grid taken, and initially, this would look unfavorable, but the advantages of this type of technique acquirement is that the player will gradually learn new, stronger techniques while keeping the more basic ones, once a "school" of fighting is fully learned, it is more efficient space ways in the grid than gathering a bunch of techniques. The box will gro w a little more if you choose to learn the "Ultimate" techniques of that school.
Of course, a drawback is that you are restricted to using all the techniques of that school, which won't be as varied as just learning a ton of different techniques. Plus, for those with Average Knowledge, they box might make it so they can only learn 2-3 techniques that are outside the school due to how much space it takes. But on the other hand, you will have a ton of variations to techniques, bringing out the full potential of your fighting style and stats if used wisely.
Another way to make techniques is to create them yourself. There will be a system that allows you to customize your own moves using a template and adjusting parameters. You can do stuff like make a fireball technique, change the colors of the flame, the size of the flame, it's damage output{when you do, it will increase/decrease the cost in relation to it's damage and size.}
For this category, there are a number of ways, such as gathering items, or fighting in a particular region while using a particular weapon related to the technique you are learning. There is a system in place that determines it, based on item labels, their values, and the character's stats as well.
An interesting way in multiplayer is if a player is a "master" of a fighting art, they can teach it to others. I'm still brainstorming what that entails, such as having those who want to learn fight alongside them or just have them bring a set of items to that player, that will be turned into the catalyst for acquiring the box of that school in your knowledge grid.
This game I've been visualizing in my head for more than 10 years, I can vividly imagine in 3D, so I can see it all already and play it. I mention this since somebody told me that not everybody can visualize, which surprised me, since I always thought it was a default thing?
